RESUMO
The crystal structure of the tetrameric glycolytic enzyme phosphoglycerate mutase from the yeast Saccharomyces cerevisiae has been determined to 1.7 A resolution in complex with the sugar substrate. The difference map indicates that 3-phosphoglycerate is bound at the base of a 12 A cleft, positioning C2 of the substrate within 3.5 A of the primary catalytic residue, histidine 8.
Assuntos
Ácidos Glicéricos/química , Fosfoglicerato Mutase/química , Saccharomyces cerevisiae/enzimologia , Sítios de Ligação , Cristalografia por Raios X , Proteínas Fúngicas/química , Ligação de Hidrogênio , Modelos Moleculares , Sulfatos/químicaRESUMO
The enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the archaea shows low sequence identity (16-20%) with its eubacterial and eukaryotic counterparts. The crystal structure of the apo GAPDH from Sulfolobus solfataricus has been determined by multiple isomorphous replacement at 2.05 A resolution. The enzyme has several differences in secondary structure when compared with eubacterial GAPDHs, with an overall increase in the number of alpha-helices. There is a relocation of the active-site residues within the catalytic domain of the enzyme. The thermostability of the S. solfataricus enzyme can be attributed to a combination of an ion pair cluster and an intrasubunit disulphide bond.
