N-terminal domain of the M1P-guanylyltransferase B-isoform like proteins.
GDP-mannose pyrophosphorylase (GTP: alpha-d-mannose-1-phosphate guanyltransferase) catalyzes the formation of GDP-d-mannose from GTP and alpha-d-mannose-1-Phosphate. It contains an N-terminal catalytic domain and a C-terminal Lefthanded-beta-Helix fold domain. GDP-d-mannose is the activated form of mannose for formation of cell wall lipoarabinomannan and various mannose-containing glycolipids and polysaccharides. The function of GDP-mannose pyrophosphorylase is essential for cell wall integrity, morphogenesis and viability. Repression of GDP-mannose pyrophosphorylase in yeast leads to phenotypes, such as cell lysis, defective cell wall, and failure of polarized growth and cell separation.