Q7YT39 (MTX4_GRARO) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: M-theraphotoxin-Gr1a Short name=M-TRTX-Gr1a Alternative name(s): Toxin GsMTx-4 Short name=GsMTx4 Short name=MTx4
Organism	Grammostola rosea (Chilean rose tarantula) (Grammostola spatulata)
Taxonomic identifier	432528 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Araneae › Mygalomorphae › Theraphosidae › Grammostola

Protein attributes

Sequence length	82 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	This cationic hydrophobic peptide inhibits a lot of different channels and has an antimicrobial activity. It blocks mechanosensitive ion channels (also named strech-activated channels or SACs), without having effect on whole-cell voltage-sensitive currents. Acts by partitioning into the membrane and perturbing the interface between the channel and the lipid bilayer without necessarily being in physical contact with the channel. Inhibits atrial fibrillation as well as the membrane motor of outer hair cells at low doses. It also binds to the voltage sensor of voltage-gated potassium channels from the archaebacterium Aeropyrum pernix (KvAP) without affecting channel gating. It has also a medium toxicity on a large spectra of sodium channels (Nav1.1/SCN1A, Nav1.2/SCN2A, Nav1.3/SCN3A, Nav1.4/SCN4A, Nav1.5/SCN5A, Nav1.6/SCN8A, Nav1.7/SCN9A), and also inhibits potassium channels Kv11.1/KCNH2 and Kv11.2/KCNH6. It also exhibits antimicrobial activities against the Gram-positive bacteria B.subtilis (MIC=0.5 µM), S.aureus (MIC=2-4 µM), and S.epidermidis (MIC=4-8 µM), and Gram-negative bacteria S.typhimurium (MIC=32.64 µM), P.aeruginosa (MIC=8-16 µM), and E.coli (MIC=8-16 µM). Ref.3 Ref.6 Ref.8 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13 Ref.14
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Domain	The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin.
Miscellaneous	This toxin does not inhibit potassium channels Kv1.1/KCNA1 (IC50>85 µM), Kv1.4/KCNA4 (IC50>85 µM) and Kv11.3/KCNH7 (IC50=53 µM).
Sequence similarities	Belongs to the huwentoxin-1 family.
Mass spectrometry	Molecular mass is 4093.9 Da from positions 47 - 81. Determined by MALDI. Ref.3

Ontologies

Keywords
Cellular component	Secreted
Domain	Knottin Signal
Molecular function	Antibiotic Antimicrobial Ionic channel inhibitor Potassium channel inhibitor Sodium channel inhibitor Toxin
PTM	Amidation Disulfide bond
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological process	defense response to bacterium Inferred from electronic annotation. Source: UniProtKB-KW pathogenesis Inferred from electronic annotation. Source: InterPro
Cellular component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	potassium channel inhibitor activity Inferred from electronic annotation. Source: UniProtKB-KW sodium channel inhibitor activity Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Signal peptide

1 – 21

21

Potential

Propeptide

22 – 46

25

PRO_0000035575

Chain

47 – 80

34

M-theraphotoxin-Gr1a

PRO_0000035576

Amino acid modifications

Modified residue

80

1

Phenylalanine amide Ref.1 Ref.6

Disulfide bond

48 ↔ 63

Ref.5 Ref.15

Disulfide bond

55 ↔ 69

Ref.5 Ref.15

Disulfide bond

62 ↔ 76

Ref.5 Ref.15

Experimental info

Sequence conflict

80

1

F → S AA sequence Ref.3

Sequence conflict

80

1

F → S AA sequence Ref.4

Sequence conflict

81

1

G → A AA sequence Ref.5

Secondary structure

1

.

.

.

.

.

.

.

82

Helix Strand Turn

Details...

Turn

57 – 59

3

Beta strand

64 – 70

7

Turn

71 – 74

4

Beta strand

75 – 78

4

Sequences

	Sequence		Length	Mass (Da)
	Q7YT39 [UniParc]. Last modified October 1, 2003. Version 1. Checksum: 1F92937F1D5DF979	FASTA	82	9,400
	10 20 30 40 50 60 MKTSVVFVIA GLALLSVVCY ASELKEQSSV NEVLSTIFHF EQPEERGCLE FWWKCNPNDD 70 80 KCCRPKLKCS KLFKLCNFSF GK

References

[1]	"cDNA sequence and in vitro folding of GsMTx4, a specific peptide inhibitor of mechanosensitive channels." Ostrow K.L., Mammoser A., Suchyna T.M., Sachs F., Oswald R.E., Kubo S., Chino N., Gottlieb P.A. Toxicon 42:263-274(2003) [PubMed: 14559077] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], SYNTHESIS OF 47-80, AMIDATION AT PHE-80. Tissue: Venom gland.
[2]	"Characterization of voltage-dependent calcium channel blocking peptides from the venom of the tarantula Grammostola rosea." Ono S., Kimura T., Kubo T. Toxicon 58:265-276(2011) [PubMed: 21740921] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom gland.
[3]	"Identification of a peptide toxin from Grammostola spatulata spider venom that blocks cation-selective stretch-activated channels." Suchyna T.M., Johnson J.H., Hamer K., Leykam J.F., Gage D.A., Clemo H.F., Baumgarten C.M., Sachs F. J. Gen. Physiol. 115:583-598(2000) [PubMed: 10779316] [Abstract] Cited for: PROTEIN SEQUENCE OF 47-81, FUNCTION, MASS SPECTROMETRY. Tissue: Venom.
[4]	"Mechanically activated channel blocker." Sachs F., Johnson J.H., Suchyna T.M. Patent number US0077286, 20-JUN-2002 Cited for: PROTEIN SEQUENCE OF 47-81. Tissue: Venom.
[5]	"Solution structure of peptide toxins that block mechanosensitive ion channels." Oswald R.E., Suchyna T.M., McFeeters R., Gottlieb P.A., Sachs F. J. Biol. Chem. 277:34443-34450(2002) [PubMed: 12082099] [Abstract] Cited for: PROTEIN SEQUENCE OF 47-81, STRUCTURE BY NMR OF 47-80, DISULFIDE BONDS.
[6]	"Target promiscuity and heterogeneous effects of tarantula venom peptides affecting Na+ and K+ ion channels." Redaelli E., Cassulini R.R., Silva D.F., Clement H., Schiavon E., Zamudio F.Z., Odell G., Arcangeli A., Clare J.J., Alagon A., de la Vega R.C., Possani L.D., Wanke E. J. Biol. Chem. 285:4130-4142(2010) [PubMed: 19955179] [Abstract] Cited for: PROTEIN SEQUENCE OF 47-80, FUNCTION, MASS SPECTROMETRY, AMIDATION AT PHE-80.
[7]	Erratum Redaelli E., Cassulini R.R., Silva D.F., Clement H., Schiavon E., Zamudio F.Z., Odell G., Arcangeli A., Clare J.J., Alagon A., de la Vega R.C., Possani L.D., Wanke E. J. Biol. Chem. 285:13314-13314(2010) Cited for: SEQUENCE REVISION.
[8]	"Tarantula peptide inhibits atrial fibrillation." Bode F., Sachs F., Franz M.R. Nature 409:35-36(2001) [PubMed: 11343101] [Abstract] Cited for: FUNCTION.
[9]	"Localization of the voltage-sensor toxin receptor on KvAP." Ruta V., MacKinnon R. Biochemistry 43:10071-10079(2004) [PubMed: 15287735] [Abstract] Cited for: FUNCTION. Tissue: Venom.
[10]	"Bilayer-dependent inhibition of mechanosensitive channels by neuroactive peptide enantiomers." Suchyna T.M., Tape S.E., Koeppe R.E. II, Andersen O.S., Sachs F., Gottlieb P.A. Nature 430:235-240(2004) [PubMed: 15241420] [Abstract] Cited for: FUNCTION, MEMBRANE-PARTITIONING, D-GSMTX4 SYNTHESIS.
[11]	"Lipid membrane interaction and antimicrobial activity of GsMTx-4, an inhibitor of mechanosensitive channel." Jung H.J., Kim P.I., Lee S.K., Lee C.W., Eu Y.J., Lee D.G., Earm Y.E., Kim J.I. Biochem. Biophys. Res. Commun. 340:633-638(2006) [PubMed: 16376854] [Abstract] Cited for: FUNCTION.
[12]	"Effects of tarantula toxin GsMTx4 on the membrane motor of outer hair cells." Fang J., Iwasa K.H. Neurosci. Lett. 404:213-216(2006) [PubMed: 16797839] [Abstract] Cited for: FUNCTION ON THE MEMBRANE MOTOR OF OUTER HAIR CELLS.
[13]	"Molecular dynamics simulations of a stretch-activated channel inhibitor GsMTx4 with lipid membranes: two binding modes and effects of lipid structure." Nishizawa M., Nishizawa K. Biophys. J. 92:4233-4243(2007) [PubMed: 17384064] [Abstract] Cited for: FUNCTION.
[14]	"Is lipid bilayer binding a common property of inhibitor cysteine knot ion-channel blockers?" Posokhov Y.O., Gottlieb P.A., Morales M.J., Sachs F., Ladokhin A.S. Biophys. J. 93:L20-L22(2007) [PubMed: 17573432] [Abstract] Cited for: FUNCTION.
[15]	"Solution structure of GsMTx-4, a peptide blocker of cation-selective stretch-activated channels." Jung H.J., Lee C.W., Earm Y.E., Kim J.I. Submitted (MAY-2002) to the PDB data bank Cited for: STRUCTURE BY NMR OF 47-80, DISULFIDE BONDS.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AY316118 mRNA. Translation: AAP79435.1.

PIR

A59371.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1LU8	NMR	-	A	47-80	[»]
1TYK	NMR	-	A	47-80	[»]

ProteinModelPortal

Q7YT39.

SMR

Q7YT39. Positions 47-80.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Organism-specific databases

ArachnoServer

AS000068. M-theraphotoxin-Gr1a.

Family and domain databases

InterPro

IPR011696. Toxin_12.
[Graphical view]

Pfam

PF07740. Toxin_12. 1 hit.
[Graphical view]

PROSITE

PS60021. HWTX_1. False negative.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

MTX4_GRARO

Accession

Primary (citable) accession number: Q7YT39
Secondary accession number(s): Q7M3T1

Entry history

Integrated into UniProtKB/Swiss-Prot:	January 16, 2004
Last sequence update:	October 1, 2003
Last modified:	December 14, 2011
This is version 57 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program