The most frequent disorder of glycosylation, PMM2-CDG, is caused by a deficiency of phosphomannomutase activity. In humans two paralogous enzymes exist, both of them require mannose 1,6-bis-phosphate or glucose 1,6-bis-phosphate as activators, but only phospho-mannomutase1 hydrolyzes bis-phosphate hexoses. Mutations in the gene encoding phosphomannomutase2 are responsible for PMM2-CDG. Although not directly causative of the disease, the role of the paralogous enzyme in the disease should be clarified. Phosphomannomutase1 could have a beneficial effect, contributing to mannose 6-phosphate isomerization, or a detrimental effect, hydrolyzing the bis-phosphate hexose activator. A pivotal role in regulating mannose-1phosphate production and ultimately protein glycosylation might be played by inosine monophosphate that enhances the phosphatase activity of phosphomannomutase1. In this paper we analyzed human phosphomannomutases by conventional enzymatic assays as well as by novel techniques such as 31P-NMR and thermal shift assay. We characterized a triple mutant of phospomannomutase1 that retains mutase and phosphatase activity, but is unable to bind inosine monophosphate.

A mutant of phosphomannomutase1 retains full enzymatic activity, but is not activated by IMP : possible implications for the disease PMM2-CDG / V. Citro, C. Cimmaruta, L. Liguori, G. Viscido, M.V. Cubellis, G. Andreotti. - In: PLOS ONE. - ISSN 1932-6203. - 12:12(2017 Dec 19), pp. e0189629.1-e0189629.18. [10.1371/journal.pone.0189629]

A mutant of phosphomannomutase1 retains full enzymatic activity, but is not activated by IMP : possible implications for the disease PMM2-CDG

V. Citro;
2017-12-19

Abstract

The most frequent disorder of glycosylation, PMM2-CDG, is caused by a deficiency of phosphomannomutase activity. In humans two paralogous enzymes exist, both of them require mannose 1,6-bis-phosphate or glucose 1,6-bis-phosphate as activators, but only phospho-mannomutase1 hydrolyzes bis-phosphate hexoses. Mutations in the gene encoding phosphomannomutase2 are responsible for PMM2-CDG. Although not directly causative of the disease, the role of the paralogous enzyme in the disease should be clarified. Phosphomannomutase1 could have a beneficial effect, contributing to mannose 6-phosphate isomerization, or a detrimental effect, hydrolyzing the bis-phosphate hexose activator. A pivotal role in regulating mannose-1phosphate production and ultimately protein glycosylation might be played by inosine monophosphate that enhances the phosphatase activity of phosphomannomutase1. In this paper we analyzed human phosphomannomutases by conventional enzymatic assays as well as by novel techniques such as 31P-NMR and thermal shift assay. We characterized a triple mutant of phospomannomutase1 that retains mutase and phosphatase activity, but is unable to bind inosine monophosphate.
Amino Acid Sequence; Congenital Disorders of Glycosylation; Diphosphonates; Enzyme Activation; Enzyme Assays; Enzyme Stability; Humans; Inosine Monophosphate; Ligands; Magnetic Resonance Spectroscopy; Molecular Docking Simulation; Mutation; Phosphotransferases (Phosphomutases); Sequence Alignment; Temperature
Settore BIO/10 - Biochimica
Settore MED/04 - Patologia Generale
Settore BIO/11 - Biologia Molecolare
Settore BIO/13 - Biologia Applicata
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/724682
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