P65165 (SUHB_MYCTU) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Inositol-1-monophosphatase SuhB
Short name=I-1-Pase
Short name=IMPase
Short name=Inositol-1-phosphatase
EC=3.1.3.25

Gene names

Name:	suhB
Ordered Locus Names:	Rv2701c, MT2775
ORF Names:	MTCY05A6.22c

Organism

Mycobacterium tuberculosis

Taxonomic identifier

1773 [NCBI]

Taxonomic lineage

Bacteria › Actinobacteria › Actinobacteridae › Actinomycetales › Corynebacterineae › Mycobacteriaceae › Mycobacterium › Mycobacterium tuberculosis complex

Protein attributes

Sequence length	290 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Catalyzes the dephosphorylation of inositol-1-phosphate (I-1-P) to yield free myo-inositol, a key metabolite in mycobacteria. Is also able to hydrolyze a variety of polyol phosphates such as glucitol-6-phosphate, inositol-2-phosphate (I-2-P), glycerol-2-phosphate, and 2'-AMP, albeit with reduced efficiency. Ref.3
Catalytic activity	Myo-inositol phosphate + H2O = myo-inositol + phosphate. Ref.3
Cofactor	Magnesium. Co2+ and Fe2+ can replace Mg2+ but lead to a partial activity (30%), and Mn2+ leads to a partial activity of 13%. Ref.3
Enzyme regulation	Inhibited by Li+ with IC50 value of 0.9 mM but not by Na+ or K+. Also inhibited by Zn2+ (IC50 value of 0.5 µM) and by concentrations of Mg2+ higher than 100 mM. Ref.3
Pathway	Polyol metabolism; myo-inositol biosynthesis; myo-inositol from D-glucose 6-phosphate: step 2/2.
Subunit structure	Homodimer. Dimerization is induced by Mg2+ binding. Ref.5
Induction	When comparing gene expression levels of the four IMPase family genes in exponential cultures of M.tuberculosis, the level of cysQ is the highest, almost equal to sigA; impA and impC are expressed at approximately 40% of this level, while suhB is lowest, at 12% of the cysQ level. Ref.3 Ref.4
Disruption phenotype	Strains lacking this gene show no difference in colony morphology and no differences in levels of phosphatidylinosotol mannosides (PIMs), lipomannan (LM), lipoarabinomannan (LAM) or mycothiol (in the absence of exogenous inositol). Ref.4
Sequence similarities	Belongs to the inositol monophosphatase family.
Biophysicochemical properties	Kinetic parameters: KM=0.177 mM for inositol-1-phosphate (at pH 8.5 and 37 degrees Celsius) Ref.3 Vmax=7.2 µmol/min/mg enzyme with inositol-1-phosphate as substrate (at pH 8.5 and 37 degrees Celsius) pH dependence: Optimum pH is 8.5. Exhibits a dramatic drop in activity at low pH, with less than 50% activity remaining at pH 7. In contrast, the activity is extremely stable at alkaline pH, with more than 50% activity remaining at pH 12. Temperature dependence: Optimum temperature is 80 degrees Celsius. Loses 80% activity after a 2 minutes incubation at 70 degrees Celsius.
Sequence caution	The sequence AAK47090.1 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.

Ontologies

Keywords
Ligand	Magnesium Metal-binding
Molecular function	Hydrolase
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological process	protein homooligomerization Inferred from physical interaction Ref.3. Source: MTBBASE
Molecular function	inositol monophosphate 1-phosphatase activity Inferred from direct assay Ref.3. Source: MTBBASE magnesium ion binding Inferred from direct assay Ref.3. Source: MTBBASE
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 290

290

Inositol-1-monophosphatase SuhB

PRO_0000142564

Regions

Region

106 – 109

4

Substrate binding By similarity

Sites

Metal binding

83

1

Magnesium 1 By similarity

Metal binding

104

1

Magnesium 1 By similarity

Metal binding

104

1

Magnesium 2 By similarity

Metal binding

106

1

Magnesium 1; via carbonyl oxygen By similarity

Metal binding

107

1

Magnesium 2 By similarity

Metal binding

235

1

Magnesium 2 By similarity

Binding site

83

1

Substrate By similarity

Binding site

206

1

Substrate By similarity

Binding site

235

1

Substrate By similarity

Experimental info

Mutagenesis

81

1

L → A: No effect on activity. 10-fold more resistant to inhibition by Li(+). Ref.3

Mutagenesis

83

1

E → D: Less than 4% of wild-type activity. Ref.3

Mutagenesis

104

1

D → N: Less than 4% of wild-type activity. Ref.3

Mutagenesis

107

1

D → N: Less than 4% of wild-type activity. Ref.3

Mutagenesis

234

1

W → L: Less than 4% of wild-type activity. Ref.3

Mutagenesis

235

1

D → N: Less than 4% of wild-type activity. Ref.3

Secondary structure

1

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290

Helix Strand Turn

Details...

Helix

8 – 33

26

Helix

55 – 74

20

Beta strand

100 – 107

8

Helix

109 – 114

6

Beta strand

120 – 127

8

Beta strand

130 – 138

9

Turn

139 – 142

4

Beta strand

143 – 148

6

Turn

149 – 151

3

Beta strand

152 – 157

6

Beta strand

160 – 163

4

Helix

172 – 174

3

Beta strand

176 – 181

6

Beta strand

183 – 185

3

Helix

188 – 198

11

Helix

199 – 201

3

Beta strand

202 – 207

6

Helix

211 – 220

10

Beta strand

224 – 231

8

Helix

233 – 245

13

Beta strand

249 – 252

4

Beta strand

262 – 267

6

Helix

269 – 271

3

Helix

272 – 280

9

Sequences

	Sequence		Length	Mass (Da)
	P65165 [UniParc]. Last modified October 11, 2004. Version 1. Checksum: 2C8A3F9A15D515CE	FASTA	290	30,027
	10 20 30 40 50 60 MTRPDNEPAR LRSVAENLAA EAAAFVRGRR AEVFGISRAG DGDGAVRAKS SPTDPVTVVD 70 80 90 100 110 120 TDTERLLRDR LAQLRPGDPI LGEEGGGPAD VTATPSDRVT WVLDPIDGTV NFVYGIPAYA 130 140 150 160 170 180 VSIGAQVGGI TVAGAVADVA ARTVYSAATG LGAHLTDERG RHVLRCTGVD ELSMALLGTG 190 200 210 220 230 240 FGYSVRCREK QAELLAHVVP LVRDVRRIGS AALDLCMVAA GRLDAYYEHG VQVWDCAAGA 250 260 270 280 290 LIAAEAGARV LLSTPRAGGA GLVVVAAAPG IADELLAALQ RFNGLEPIPD

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence." Cole S.T., Brosch R., Parkhill J., Garnier T., Churcher C.M., Harris D.E., Gordon S.V., Eiglmeier K., Gas S., Barry C.E. III, Tekaia F., Badcock K., Basham D., Brown D., Chillingworth T., Connor R., Davies R.M., Devlin K. , Feltwell T., Gentles S., Hamlin N., Holroyd S., Hornsby T., Jagels K., Krogh A., McLean J., Moule S., Murphy L.D., Oliver S., Osborne J., Quail M.A., Rajandream M.A., Rogers J., Rutter S., Seeger K., Skelton S., Squares S., Squares R., Sulston J.E., Taylor K., Whitehead S., Barrell B.G. Nature 393:537-544(1998) [PubMed: 9634230] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: ATCC 25618 / H37Rv.
[2]	"Whole-genome comparison of Mycobacterium tuberculosis clinical and laboratory strains." Fleischmann R.D., Alland D., Eisen J.A., Carpenter L., White O., Peterson J.D., DeBoy R.T., Dodson R.J., Gwinn M.L., Haft D.H., Hickey E.K., Kolonay J.F., Nelson W.C., Umayam L.A., Ermolaeva M.D., Salzberg S.L., Delcher A., Utterback T.R. , Weidman J.F., Khouri H.M., Gill J., Mikula A., Bishai W., Jacobs W.R. Jr., Venter J.C., Fraser C.M. J. Bacteriol. 184:5479-5490(2002) [PubMed: 12218036] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: CDC 1551 / Oshkosh.
[3]	"Purification and biochemical characterization of Mycobacterium tuberculosis SuhB, an inositol monophosphatase involved in inositol biosynthesis." Nigou J., Dover L.G., Besra G.S. Biochemistry 41:4392-4398(2002) [PubMed: 11914086] [Abstract] Cited for: FUNCTION, CATALYTIC ACTIVITY, SUBSTRATE SPECIFICITY, COFACTOR, ENZYME REGULATION, BIOPHYSICOCHEMICAL PROPERTIES, MUTAGENESIS OF LEU-81; GLU-83; ASP-104; ASP-107; TRP-234 AND ASP-235. Strain: ATCC 25618 / H37Rv.
[4]	"Inositol monophosphate phosphatase genes of Mycobacterium tuberculosis." Movahedzadeh F., Wheeler P.R., Dinadayala P., Av-Gay Y., Parish T., Daffe M., Stoker N.G. BMC Microbiol. 10:50-50(2010) [PubMed: 20167072] [Abstract] Cited for: DISRUPTION PHENOTYPE, INDUCTION. Strain: ATCC 25618 / H37Rv.
[5]	"Dimerization of inositol monophosphatase Mycobacterium tuberculosis SuhB is not constitutive, but induced by binding of the activator Mg2+." Brown A.K., Meng G., Ghadbane H., Scott D.J., Dover L.G., Nigou J., Besra G.S., Futterer K. BMC Struct. Biol. 7:55-55(2007) [PubMed: 17725819] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS), SUBUNIT. Strain: ATCC 25618 / H37Rv.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

BX842580 Genomic DNA. Translation: CAB09491.1.
AE000516 Genomic DNA. Translation: AAK47090.1. Different initiation.

PIR

H70530.

RefSeq

NP_217217.1. NC_000962.2.
NP_337276.1. NC_002755.2.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2Q74	X-ray	2.60	A/B/C	1-290	[»]

ProteinModelPortal

P65165.

SMR

P65165. Positions 5-286.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblBacteria

EBMYCT00000001952; EBMYCP00000001952; EBMYCG00000001950.
EBMYCT00000071246; EBMYCP00000069305; EBMYCG00000071241.

GeneID

887210.
925526.

GenomeReviews

Gene locus MT2775 in contig AE000516_GR.
Gene locus Rv2701c in contig AL123456_GR.

KEGG

mtc:MT2775.
mtu:Rv2701c.

PATRIC

18127844. VBIMycTub22151_3021.

TIGR

MT2775.

Organism-specific databases

TubercuList

Rv2701c.

Phylogenomic databases

GeneTree

EBGT00050000015694.

HOGENOM

HBG730251.

OMA

VNFIVQK.

PhylomeDB

P65165.

ProtClustDB

CLSK792016.

Family and domain databases

InterPro

IPR020583. Inositol_monoP_metal-BS.
IPR000760. Inositol_monophosphatase.
IPR020550. Inositol_monophosphatase_CS.
[Graphical view]

KO

K01092.

PANTHER

PTHR20854. Inositol_P. 1 hit.

Pfam

PF00459. Inositol_P. 1 hit.
[Graphical view]

PRINTS

PR00377. IMPHPHTASES.

PROSITE

PS00629. IMP_1. 1 hit.
PS00630. IMP_2. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

SUHB_MYCTU

Accession

Primary (citable) accession number: P65165
Secondary accession number(s): O07203

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 11, 2004
Last sequence update:	October 11, 2004
Last modified:	January 25, 2012
This is version 51 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program