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metallo.txt

----------------------------------------------------------------------------
        UniProt - Swiss-Prot Protein Knowledgebase
        SIB Swiss Institute of Bioinformatics; Geneva, Switzerland
        European Bioinformatics Institute (EBI); Hinxton, United Kingdom
        Protein Information Resource (PIR); Washington DC, USA
----------------------------------------------------------------------------

Description: Metallothioneins: classification and list of entries
Name:        metallo.txt
Release:     2017_07 of 05-Jul-2017

----------------------------------------------------------------------------

This document provides both a brief  description  of  the  classification  of
metallothioneins into families as developed by Pierre-Alain Binz and Jeremias
H.R. Kagi as well as the list, classified  by  family, of the metallothionein
entries in  UniProtKB/Swiss-Prot.   The  definition  of  the  metallothionein
superfamily and its subdivisions is presented at the bottom of this file. The
description of the criteria  characterising  all families and  subfamilies is
to be found at:

  http://www.bioc.unizh.ch/mtpage/MT.html


                       ========================
                       Metallothionein families
                       ========================

Introduction
------------

Metallothioneins (MTs)  constitute  a  superfamily  of  low  molecular  weight
cysteine-rich metalloproteins  and  metallopeptides responsible for regulating
the intracellular  supply  of  the biologically essential zinc and copper ions
and for  protecting cells from the deleterious effects of exposure to elevated
amounts of  these  and non-essential polarizable transition and posttransition
metal ions such as Cd2+, Hg2+ and others. Since its discovery as a cadmium and
zinc containing  protein  in  horse  kidney by Margoshes and Vallee [1] MT has
been an  object  of  intensive  study in various branches of the life sciences
[2,3]. MT is now known to occur in all animal phyla examined so far as well as
in certain fungi, plants and cyanobacteria.

In mammals,  20 totally conserved cysteine residues (Cys) bind, in the reduced
form, a  complement of 7 equivalents of polarizable bivalent metal ions giving
rise to  two  unique metal-thiolate clusters with characteristic spectroscopic
features [4].  The  spontaneous  refolding  of the native structure upon metal
addition attests  to  a guiding role of the positions of the Cys and other AAs
conserved in  the polypeptide chain. The invertebrate holo-MTs studied thusfar
display similar  clusters  with structural and compositional variations due to
different numbers and relative positions of the Cys residues on the
polypeptide chain.

An empirical  classification  into three classes was proposed by Fowler et al.
[5] and  Kojima  [6].  Members  of Class I are defined to include polypeptides
related in  the  positions  of the Cys to equine MT-1B while those of class II
display none  or very distant correspondence in this respect. Class I subsumes
besides the  vertebrate  MTs  all  presently  known  crustacean  and molluscan
sequences. Class  III  MTs  are  polyisopeptides  composed  of atypical gamma-
glutamylcysteinyl units  and  are no therefore direct gene products [5]. Since
this classification  system  does  not allow to differentiate clearly patterns
of structural  similarities we have now grouped all proteinaceous MT sequences
(Class I  and  Class  II)  into  families  of  phylogenetically  related  and,
accordingly, alignable   sequences.   The   subclassification   discriminating
subfamilies and  subgroups  of  MT sequences is based on phylogenetic analyses
inferred from both amino-acid and polynucleotide sequences [7-9].

The web  page  containing  all details of the classification system, including
strategy and results is to be found at:

           http://www.bioc.uzh.ch/mtpage/MT.html


References
----------

[1] Margoshes M., Vallee B.L.
    A cadmium protein from equine kidney cortex.
    J. Am. Chem. Soc. 79:4813-4814(1957).

[2] Kagi J.H.R.
    Overview of Metallothioneins.
    Methods Enzymol. 205:613-626(1991).

[3] Kagi J.H.R., Kojima Y.
    Chemistry and biochemistry of metallothionein.
    Experientia Suppl. 52:25-61(1987).

[4] Kagi J.H.R., Schaffer A.
    Biochemistry of metallothionein.
    Biochemistry 27:8509-8515(1988).

[5] Fowler B.A., Hildebrand C.E., Kojima Y., Webb M.
    Nomenclature of metallothionein.
    Experientia Suppl. 52:21(1987).

[6] Kojima Y.
    Definitions and nomenclature of metallothioneins.
    Methods Enzymol. 205:8-10(1991).

[7] Binz P.-A.
    Metallothioneins: studies on molecular evolution and on the structural
    and chiroptical features of their metal thiolate clusters.
    PhD thesis, University Zurich, Switzerland (1996).

[8] Kojima Y., Binz P.-A., Kagi J.H.R.
    Nomenclature of metallothionein: proposal for a revision.
    (In) Metallothionein IV, Klaassen C. (Ed.), pp3-6, Birkhauser Verlag,
    Basel, (1999).

[9] Binz P.-A., Kagi J.H.R.
    Metallothionein: molecular evolution and classification.
    (In) Metallothionein IV, Klaassen C. (Ed.), pp7-13, Birkhauser Verlag,
    Basel, (1999).


------------------------------------------------------------------------------

               =============================================
               Swiss-Prot entries for metallothioneins (MTs)
               =============================================

Notes:

 Subdiv. = subdivision
           Subdivisions are described for each family

 Rem.    = remarks:
           v: variant(s) known
           c: conflict(s) known
           p: partial sequence

 Source  = molecular source:
           AA: protein sequence
           NA: nucleic acid sequence


The criteria used for the classifications are described at the bottom of this
document.


========================
Family 1: vertebrate MTs
========================

Pattern: K-x(1,2)-C-C-x-C-C-P-x(2)-C
3D structure status: available for mouse  Cd7-MT-1 (PDB: 1DFS, 1DFT)
                                   human  Cd7-MT-2 (PDB: 1HMU, 2HMU)
                                   rabbit Cd7-MT-2 (PDB: 1MRB, 2MRB)
                                   rat    Cd7-MT-2 (PDB: 1MRT, 2MRT, 4MT2)
                                   rat Cd5Zn2-MT-2 (Braun et al. 1992,
                                                    PNAS USA 89:10124-10128,
                                                    not in PDB)
Known taxonomic range: vertebrata
Multiple sequence alignment: yes
Phylogenetic trees: yes
Subdivisions: m1: mammalian MT-1
              m2: mammalian MT-2
              m3: mammalian MT-3
              m4: mammalian MT-4
              m : mammalian MT
              a1: avian MT-1
              a2: avian MT-2
              a : avian MT
              r : reptilian MT
              t : teleost MT
              s : sharks MT
              b : batracian MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_BOVIN   (P58280)    M1             AA
MT1A_BOVIN  (P67983)    m1       c     AA/NA
MT1H_BOVIN  (P55942)    m              AA
MT2_BOVIN   (P68301)    m2             AA
MT2H_BOVIN  (P55943)    m              AA
MT1_CANLF   (O19000)    m1             AA/NA
MT2_CANLF   (Q9XST5)    m2             AA/NA
MT1_CRIGR   (P02804)    m1             NA
MT2_CRIGR   (P67981)    m2             NA
MT2_CRILO   (P68041)    m2             NA
MT2_MESAU   (P17808)    m2             NA
MT1A_HORSE  (P02800)    m1       v     AA
MT1B_HORSE  (P02801)    m2             AA
MT1_MOUSE   (P02802)    m1       c     AA/NA
MT2_MOUSE   (P02798)    m2       c     AA/NA
MT1A_PIG    (P49068)    m1       c     NA
MT1C_PIG    (P79376)    m1             NA
MT1D_PIG    (P79377)    m1             NA
MT1E_PIG    (P79431)    m1             NA
MT1F_PIG    (P79378)    m1             NA
MT2A_PIG    (P79379)    m2             NA
MT2B_PIG    (P79380)    m2             NA
MT1A_RABIT  (P11957)    m1             AA/NA
MT2A_RABIT  (P18055)    m              AA
MT2B_RABIT  (P80289)    m              AA
MT2C_RABIT  (P80290)    m              AA
MT2D_RABIT  (P80291)    m              AA
MT2E_RABIT  (P80292)    m              AA
MT1_RAT     (P02803)    m1             AA/NA
MT2_RAT     (P04355)    m2             AA/NA
MT1A_SHEEP  (P67982)    m1       c     NA
MT1B_SHEEP  (P09577)    m1             NA
MT1C_SHEEP  (P09578)    m1             NA
MT2_SHEEP   (P68302)    m2             NA
MT2_STECO   (P14425)    m1             AA
MT1_CHLAE   (P02797)    m1             NA
MT2_CHLAE   (P68304)    m2             NA
MT1A_HUMAN  (P04731)    m1             NA
MT1B_HUMAN  (P07438)    m1             NA
MT1E_HUMAN  (P04732)    m1             AA/NA
MT1F_HUMAN  (P04733)    m1             AA/NA
MT1G_HUMAN  (P13640)    m1             AA/NA
MT1H_HUMAN  (P80294)    m1             AA/NA
MT1L_HUMAN  (Q93083)    m1             AA/NA
MT1M_HUMAN  (Q8N339)    m1             NA
MT1X_HUMAN  (P80297)    m1             AA/NA
MT2_HUMAN   (P02795)    m2             AA/NA
MT2_MACFA   (P68303)    m2             NA
MT2_PONAB   (Q5NVS0)    m2             NA
MT3_BOSMU   (Q2MJS5)    m3             NA
MT3_BOVIN   (P37359)    m3             AA
MT3_HORSE   (P37360)    m3             AA
MT3_HUMAN   (P25713)    m3             AA/NA
MT3_MACFA   (Q2PFZ0)    m3             NA
MT3_MOUSE   (P28184)    m3             NA
MT3_PIG     (P55944)    m3             NA
MT3_RABIT   (Q2PS21)    m3             NA
MT3_RAT     (P37361)    m3             NA
MT3_SHEEP   (Q8MKE4)    m3             NA
MT4_CANLF   (Q9TUI5)    m4             NA
MT4_HUMAN   (P47944)    m4             NA
MT4_MOUSE   (P47945)    m4             NA
MT_BALMY    (O18842)    m              NA
MT_ANAPL    (P68494)    a1             AA/NA
MT_CAIMO    (P68495)    a1             AA/NA
MT_CHICK    (P68497)    a1             AA/NA
MT1_COLLI   (P15786)    a1             AA
MT2_COLLI   (P15787)    a2             AA
MTA_COLVI   (P27086)    a        p     NA
MTB_COLVI   (P27087)    a        p     NA
MT_MELGA    (P68498)    a1             NA
MT_PHACO    (P68499)    a1       p     NA
MT_PODSI    (Q708T3)    r              NA
MT1_DANRE   (P52722)    t              NA
MT2_DANRE   (Q7ZSY6)    t              NA
MT_CARAU    (P52723)    t        c     NA
MTA_CARCW   (Q8AWG2)    t              NA
MTB_CARCW   (Q8AWG1)    t              NA
MTA_CHAAC   (O93593)    t              NA
MTB_CHAAC   (P52724)    t              NA
MTA_CHIHA   (P68506)    t              NA
MTB_CHIHA   (P62711)    t              NA
MTA_CHIRA   (P62338)    t              NA
MTB_CHIRA   (P62679)    t              NA
MT1_CYPCA   (O13269)    t              NA
MT2_CYPCA   (Q9I9I0)    t              NA
MTA_CYPS1   (Q92044)    t              NA
MTB_DICLA   (Q9PTG9)    t              NA
MT_ESOLU    (P25127)    t              NA
MT_GADMO    (P51902)    t        c     NA
MT_GOBCO    (Q800D3)    t              NA
MTA_GYMAC   (P68507)    t              NA
MTB_GYMAC   (P62713)    t              NA
MT_ICTPU    (O93571)    t              NA
MT_LITMO    (Q8UVY1)    t              NA
MT_LIZAU    (O13257)    t              NA
MTB_MORSA   (P62712)    t              NA
MT_BARBB    (P25128)    t              NA
MTA_NOTNE   (P62339)    t              NA
MTB_NOTNE   (P62680)    t              NA
MTA_ONCMY   (P68503)    t              NA
MTB_ONCMY   (P68501)    t              NA
MT_OREAU    (Q7ZZP9)    t              NA
MT_OREMO    (P52726)    t        c     NA
MT_ORYLA    (Q6S4N8)    t              NA
MTA_TREBE   (O93609)    t              NA
MTB_TREBE   (P62678)    t              NA
MTA_PAGBO   (P68508)    t              NA
MTB_PAGBO   (P62681)    t              NA
MT_PAGMA    (Q9IB50)    t              NA
MTA_PARCR   (O93450)    t              NA
MTB_PARCR   (P62682)    t              NA
MT_PERFL    (P52725)    t              NA
MT_PLEAT    (Q6XUW5)    t              NA
MT_PLEPL    (P07216)    t              AA/NA
MT_PSEAM    (P55945)    t              AA/NA
MT_RUTRU    (P80593)    t              AA
MTA_SALAL   (P68505)    t        c     NA
MTB_SALAL   (P68502)    t        c     NA
MTA_SALSA   (P68504)    t              NA
MTB_SALSA   (P52720)    t              NA
MTA_SPAAU   (P52727)    t              NA
MTA_THECR   (P52721)    t              NA
MT_ZOAVI    (P52728)    t              NA
MT_SCYTO    (Q6J1T3)    s              NA
MT_AMBME    (O42152)    b              NA
MT_XENLA    (Q05890)    b              NA


=====================
Family 2: mollusc MTs
=====================

Pattern: C-x-C-x(3)-C-T-G-x(3)-C-x-C-x(3)-C-x-C-K
3D structure status: not available
Known taxonomic range: pelecypoda, gastropoda
Multiple sequence alignment: yes
Phylogenetic trees: yes
Subdivisions: mo1: mussel MT-1
              mo2: mussel MT-2
              mog: gastropod MT
              mo : other mollusc MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT_CRAVI    (P23038)    mo             AA/NA
MT_DREPO    (Q94550)    mo             NA
MT10A_MYTED (P80246)    mo1            AA/NA
MT10B_MYTED (O62554)    mo1            NA
MT12_MYTED  (P80247)    mo1      c     AA/NA
MT13_MYTED  (P80248)    mo1            AA/NA
MT14_MYTED  (P80249)    mo1            AA/NA
MT21_MYTED  (P80251)    mo2      v     AA
MT22_MYTED  (P80252)    mo2            AA/NA
MT23A_MYTED (P69153)    mo2            AA
MT23B_MYTED (P80258)    mo2            AA
MT23A_MYTGA (P69154)    mo2            NA
MT_PERVI    (Q9U568)    mo       c     NA
MT_ARIAR    (P55946)    mog      v     AA
MTCD_HELPO  (P33187)    mog            AA
MTCU_CALSI  (Q9U620)    mog            NA
MTCU_HELPO  (P55947)    mog            AA


========================
Family 3: crustacean MTs
========================

Pattern: P-[GD]-P-C-C-x(3,4)-C-x-C
3D structure status: available for blue crab Cd6-MT-I (PDB: 1DMC, 1DMD, 1DME, 1DMF)
                               for mud crab Cd6-MT1 (Not yet in PDB)
Known taxonomic range: crustacea
Multiple sequence alignment: yes
Phylogenetic trees: yes
Subdivisions: c : crustacean MT
              c1: crustacean MT-1
              c2: crustacean MT-2

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT_CARMA    (P55948)    c2       v     AA
MT1_CALSI   (P55949)    c1       v     AA
MT2_CALSI   (P55950)    c2       v     AA
MT1_SCYSE   (P02805)    c1             AA
MT2_SCYSE   (P02806)    c2             AA
MT1_HOMAM   (P29499)    c              AA
MT_ASTAS    (P55951)    c        v     AA
MT_POTPO    (P55952)    c              AA


===========================
Family 4: echinodermata MTs
===========================

Pattern: P-D-x-K-C-V-C-C-x(5)-C-x-C-x(4)-C-C-x(4)-C-C-x(4,6)-C-C
3D structure status: available for sea urchin Cd7-MTA (1qjk, 1qjl)
Known taxonomic range: echinoidea
Multiple sequence alignment: yes
Phylogenetic trees: yes
Subdivisions: e1: echinodermata MT type 1
              e2: echinodermata MT type 2

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT_LYTPI    (O02033)    e2             NA
MT_PARLI    (P80367)    e2             AA
MTA_STRPU   (P04734)    e1       c     NA
MTB_STRPU   (Q27287)    e1             NA
MTA_SPHGR   (Q26497)    e2       p     NA
MTB_SPHGR   (Q26496)    e2       p     NA
MT_STENE    (P55953)    e1             NA


=====================
Family 5: diptera MTs
=====================

Pattern: C-G-x(2)-C-x-C-x(2)-Q-x(5)-C-x-C-x(2)-D-C-x-C
3D structure status: not available
Known taxonomic range: diptera
Multiple sequence alignment: yes
Phylogenetic trees: no
Subdivisions: d1: diptera MT type 1
              d2: diptera MT type 2

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_DROAN   (P61873)    d1             NA
MT1_DROME   (P04357)    d1             NA
MT1_DROSI   (P61874)    d1             NA
MT2_DROME   (P11956)    d2             NA
MT3_DROME   (Q9VDN2)    d2             NA
MT4_DROME   (Q8I9B4)    d2             NA


======================
Family 6: nematoda MTs
======================

Pattern: K-C-C-x(3)-C-C
3D structure status: not available
Known taxonomic range: secernentea
Multiple sequence alignment: yes
Phylogenetic trees: no
Subdivisions: n1: nematoda MT type 1
              n2: nematoda MT type 2

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_CAEEL   (P17511)    n1       c     NA
MT2_CAEEL   (P17512)    n2             NA


=====================
Family 7: ciliata MTs
=====================

Pattern: -
3D structure status: not available
Known taxonomic range: ciliata (protozoa)
Multiple sequence alignment: no
Phylogenetic trees: no
Subdivisions: ci: ciliata MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_TETPI   (P80394)    ci             AA/NA
MT1_TETPY   (O97388)    ci             AA/NA
MT1_TETTH   (Q8T6B3)    ci             NA
MTCD_TETTH  (Q8WSW3)    ci             NA


=====================
Family 8: fungi-I MTs
=====================

Pattern: C-G-C-S-x(4)-C-x-C-x(3,4)-C-x-C-S-x-C
3D structure status: available for N.crassa Cu6-MT (PDB: 1T2Y)
Known taxonomic range: basidiomycotina, deuteromycotina, ascomycotina
Multiple sequence alignment: yes
Phylogenetic trees: no
Subdivisions: f1: fungi-I MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT_AGABI    (P04358)    f1             AA
MT1_COLGL   (Q99334)    f1             NA
MT2_COLGL   (Q00369)    f1             NA
MT1_NECLU   (P84865)    f1             AA
MT_NEUCR    (P02807)    f1       c     AA/NA


======================
Family 9: fungi-II MTs
======================

Pattern: -
3D structure status: not available
Known taxonomic range: deuteromycotina
Multiple sequence alignment: no
Phylogenetic trees: no
Subdivisions: f2: fungi-II MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_CANGA   (P15113)    f2             AA/NA


========================
Family 10: fungi-III MTs
========================

Pattern: -
3D structure status: not available
Known taxonomic range: deuteromycotina
Multiple sequence alignment: no
Phylogenetic trees: no
Subdivisions: f3

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT2_CANGA   (P15114)    f3       v     AA/NA


=======================
Family 11: fungi-IV MTs
=======================

Pattern: C-X-K-C-x-C-x(2)-C-K-C
3D structure status: not available
Known taxonomic range: ascomycotina
Multiple sequence alignment: no
Phylogenetic trees: no
Subdivisions: f4: fungi-IV MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_YARLI   (P41927)    f4             NA
MT2_YARLI   (P41928)    f4             NA
MT3_YARLI   (Q9HFD0)    f4             NA
MT4_YARLI   (Q9HFC9)    f4             NA


======================
Family 12: fungi-V MTs
======================

Pattern: -
3D structure status: PDB: 1AOO, 1AQQ, 1AQR, 1AQS
Known taxonomic range: ascomycotina
Multiple sequence alignment: yes
Phylogenetic trees: no
Subdivisions: f5: fungi-V MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MTCU1_YEAST (P0CX80)    f5             AA/NA
MTCU2_YEAST (P0CX81)    f5             AA/NA


=======================
Family 13: fungi-VI MTs
=======================

Pattern: -
3D structure status: not available
Known taxonomic range: ascomycotina
Multiple sequence alignment: no
Phylogenetic trees: no
Subdivisions: f6: fungi-VI MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
CRS5_YEAST  (P41902)    f6             NA


=========================
Family 14: prokaryota MTs
=========================

Pattern: K-C-A-C-x(2)-C-L-C
3D structure status: not available
Known taxonomic range: cyanobacteria
Multiple sequence alignment: yes
Phylogenetic trees: no
Subdivisions: pr: prokaryota MT

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT_SYNE7    (P30331)    pr             AA/NA
MT_SYNSP    (P08002)    pr             AA
MT_THEVL    (P30565)    pr             NA


====================
Family 15: plant MTs
====================

Pattern: [YFH]-x(5,25)-C-[SKD]-C-[GA]-[SDPAT]-x(0,1)-C-x-[CYF]
         Note: yields all plant sequences, but also MTCU_HELPO  (P55947) and the non-MT
         ITB3_HUMAN  (P05106)
3D structure status: not available
Known taxonomic range: angiospermae (magnolophyta)
Multiple sequence alignment: yes
Phylogenetic trees: yes
Subdivisions: p1 : plant MT type 1
              p2 : plant MT type 2
              p3 : plant MT type 3
              p21: plant MT type 2x1
              pec: plant EC MT-like protein

Swiss-Prot              Subdiv.  Rem.  Source
Entry name  AC
--------------------    -------  ----  ------
MT1_CASGL   (Q39511)    p1             NA
MT1_CICAR   (Q39458)    p1             NA
MT1_FESRU   (O24528)    p1             NA
MT1_HORVU   (P26571)    p1             NA
MT1_MAIZE   (P30571)    p1             NA
MT1A_ORYSI  (A2ZH20)    p1             NA
MT1A_ORYSJ  (P0C5B3)    p1             NA
MT1B_ORYSJ  (Q10N03)    p1             NA
MT1_PEA     (P20830)    p1             NA
MT1_TRIRP   (P43399)    p1             NA
MT1A_VICFA  (Q41669)    p1             NA
MT1B_VICFA  (Q41670)    p1             NA
MT1_WHEAT   (P43400)    p1             NA
MT2_ACTDE   (P43390)    p2             NA
MT2A_ARATH  (P25860)    p2       c     NA
MT2B_ARATH  (Q38805)    p2             NA
MT21_BRAJU  (P56168)    p2             NA
MT22_BRAJU  (P69163)    p2             NA
MT23_BRAJU  (P56170)    p2             NA
MT25_BRAJU  (P56172)    p2             NA
MT2_BRANA   (Q96353)    p2       p     NA
MT2_BRACM   (P69164)    p2       c     NA
MT2_BRARP   (Q39269)    p2             NA
MT2_CICAR   (Q39459)    p2       p     NA
MT1_COFAR   (P43396)    p2             NA
MT2_FRAAN   (P93134)    p2             NA
MT2_MALDO   (O24058)    p2             NA
MT2_MUSAC   (O22319)    p2             NA
MT2_NICGU   (Q40396)    p2             NA
MT2_NICPL   (Q40410)    p2             NA
MT2A_ORYSJ  (P94029)    p2             NA
MT2B_ORYSJ  (Q5JM82)    p2             NA
MT2C_ORYSI  (A2XZL0)    p2             NA
MT2C_ORYSJ  (A3AZ88)    p2             NA
MT2_RICCO   (P30564)    p2             NA
MT2A_SOLLC  (Q40157)    p2             NA
MT2B_SOLLC  (Q40158)    p2       c     NA
MT2X_SOLLC  (Q43512)    p2             NA
MT2Y_SOLLC  (Q43513)    p2             NA
MT2Z_SOLLC  (Q43515)    p2             NA
MT2_TRIRP   (P43398)    p2             NA
MT2_VICFA   (Q41657)    p2             NA
MT1_ERYGU   (P20238)    p2       c     NA
MT1A_ARATH  (P43392)    p21            NA
MT1B_ARATH  (Q38803)    p21            NA
MT1C_ARATH  (Q38804)    p21            NA
MT54_BRANA  (P43402)    p21            NA
MT3_ACTDE   (P43389)    p3             NA
MT3_CARPA   (Q96386)    p3             NA
MT3_MALDO   (O24059)    p3             NA
MT3_MUSAC   (Q40256)    p3             NA
MT3A_ORYSI  (A2WLS0)    p3             NA
MT3A_ORYSJ  (A1YTM8)    p3             NA
MT3B_ORYSI  (A2Y1D7)    p3             NA
MT3B_ORYSJ  (A3B0Y1)    p3             NA
MT3_PICGL   (Q40854)    p3             NA
MT3_PRUAV   (O48951)    p3             NA
MT4A_ORYSJ  (Q0IMG5)    p4             NA
MT4B_ORYSJ  (Q2QNE8)    p4             NA
MT4C_ORYSJ  (Q2QNC3)    p4             NA
MT4A_ARATH  (P93746)    pec            NA
MT4B_ARATH  (Q42377)    pec            NA
EC_MAIZE    (P43401)    pec            NA
MT21A_ORYSJ (Q109B0)    pec            NA
EC1_WHEAT   (P30569)    pec      c     AA/NA
EC3_WHEAT   (P30570)    pec            NA


==========================================================================
Family 99: phytochelatins and other non-proteinaceous MT-like polypeptides
==========================================================================

Note: gammaglutamyl-cysteinyl units, these are not proteins.
3D structure status: not available
Known taxonomic range: viridiplantae
Subdivisions: not defined


------------------------------------------------------------------------------


    ==================================================================
    Definition of the metallothionein superfamily and its subdivisions
    ==================================================================

The metallothionein  superfamily  is  defined phenomenologically as comprising
all polypeptides  which  resemble  equine  renal metallothionein in several of
their features  (Nordberg  &  Kojima  1979,  Fowler et al. 1987). Such general
features are  low  molecular  weight, high metal content, characteristic amino
acid composition  (high  Cys  content,  low  content  of  aromatic  amino acid
residues), unique amino acid sequence with characteristic distribution of Cys,
i.e. Cys-X-Cys   and  spectroscopic  manifestations  characteristic  of  metal
thiolate clusters.

A MT  family  subsumes  MTs  which share a particular set of sequence specific
characters. Members  of a family can belong to only one family and are thought
to be  evolutionary  related.  The  inclusion of an MT in a family presupposes
that its  amino  acid sequence is alignable with that of all members. A common
and exclusive  sequence  pattern,  a  profile  and  a  phylogenetic  tree  can
therefore be  connected  with  each  family.  Each family is identified by its
number and its taxonomic range. An example is Family 1: vertebrate MTs.

A MT subfamily contains MTs which in addition to the family characters share a
set of  more stringent phylogenetic features. These extra criteria are usually
specific monophyletic  relationships among the sequences of proteins and/or of
nucleotide segments in the genes (5' or 3' untranscribed portion of the genes,
5' or  3'  untranslated portions of the nucleotide sequences, exons, introns).
If relevant  other  differentiating  criteria  can  also  be included, such as
presence, conservation  or  repetition  of  sequence  patterns. A subfamily is
usually abbreviated  with  a  letter character followed, if necessary, with an
arabic number. An example is m1: mammalian MT-1.

A MT  subgroup represents, as a result of statistically validated phylogenetic
analyses, a   branch   of  MT  sequences  of  a  subfamily  which  is  clearly
distinguishable in  a  tree by its monophyletic character. An example is m2U2:
ungulate MT-2, subgroup of the m2 subfamily.

Isoforms or allelic forms are specifiable as members of subgroups, subfamilies
and families.  They  are named using the nomenclature system defined in Kojima
et al. (submitted), i.e. human MT-1E.

In addition, in cases where it is justifiable, one can define clans. A clan is
a set  of  partial or total amino acid or polynucleotide sequences, subgroups,
subfamilies, families  or  combinations  of  them  which  share characters not
defined by  the  above  classification criteria. They can be related to common
spatial structure,   thermodynamic   properties,   metal  binding  properties,
functionally related  characters or other relevant features. A clan is defined
by the  property  common  to its members. The abbreviation should reflect this
property.

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