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Phosphomannose isomerase (EC 5.3.1.8) (PMI) [1,2] is the enzyme that catalyzes the interconversion of mannose-6-phosphate and fructose-6-phosphate. In eukaryotes, it is involved in the synthesis of GDP-mannose which is a constituent of N- and O-linked glycans as well as GPI anchors. In prokaryotes, it is involved in a variety of pathways including capsular polysaccharide biosynthesis and D-mannose metabolism.

Three classes of PMI have been defined on the basis of sequence similarities [1]. The first class comprises all known eukaryotic PMI as well as the enzyme encoded by the manA gene in enterobacteria such as Escherichia coli. Class I PMI's are proteins of about 42 to 50 Kd which bind a zinc ion essential for their activity.

As signature patterns for class I PMI, we selected two conserved regions. The first one is located in the N-terminal section of these proteins, the second in the C-terminal half. Both patterns contain a residue involved [3] in the binding of the zinc ion.

Proudfoot A.E.I.

November 1997 / Text revised.

PROSITE methods (with tools and information) covered by this documentation:

PMI_I_1, PS00965; Phosphomannose isomerase type I signature 1  (PATTERN)

Consensus pattern: Y-x-D-x-N-H-K-P-E E is a zinc ligand Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00965 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00965 • Scan Swiss-Prot/TrEMBL entries against PS00965 • view ligand binding statistics

Matching PDB structures: 1PMI 2WFP 3H1M 3H1W ... [ALL]

PMI_I_2, PS00966; Phosphomannose isomerase type I signature 2  (PATTERN)

Consensus pattern: H-A-Y-[LIVM]-x-G-x(2)-[LIVM]-E-x-M-A-x-S-D-N-x-[LIVM]-R-A-G-x-T-P-K H is a zinc ligand Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00966 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00966 • Scan Swiss-Prot/TrEMBL entries against PS00966 • view ligand binding statistics

Matching PDB structures: 1PMI 2WFP 3H1M 3H1W ... [ALL]

1	Authors	Proudfoot A.E.I., Turcatti G., Wells T.N., Payton M.A., Smith D.J.
	Title	Purification, cDNA cloning and heterologous expression of human phosphomannose isomerase.
	Source	Eur. J. Biochem. 219:415-423(1994).
	PubMed ID	8307007

2	Authors	Coulin F., Magnenat E., Proudfoot A.E.I., Payton M.A., Scully P., Wells T.N.C.
	Title	Identification of Cys-150 in the active site of phosphomannose isomerase from Candida albicans.
	Source	Biochemistry 32:14139-14144(1993).
	PubMed ID	8260497

3	Authors	Cleasby A., Wonacott A., Skarzynski T., Hubbard R.E., Davies G.J., Proudfoot A.E.I., Bernard A.R., Payton M.A., Wells T.N.C.
	Title	The x-ray crystal structure of phosphomannose isomerase from Candida albicans at 1.7 angstrom resolution.
	Source	Nat. Struct. Biol. 3:470-479(1996).
	PubMed ID	8612079

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