|PROSITE documentation PDOC00746|
Phosphomannose isomerase (EC 18.104.22.168) (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 . 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  in the binding of the zinc ion.Expert(s) to contact by email:
November 1997 / Text revised.
PROSITE methods (with tools and information) covered by this documentation:
|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).|
|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.|
|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).|