Biochemical characterization of five GH130-family enzymes from Caldanaerobius polysaccharolyticus ATCC BAA-17 and insights on their metabolic role and reaction mechanisms

GH130;Enzyme;Phosphorolysis;Mannan;Thermophilic

Muller Paul, Hans M ; Cann ; Isaac

关键词: GH130;    Enzyme;    Phosphorolysis;    Mannan;    Thermophilic;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/95627/MULLERPAUL-THESIS-2016.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Proteins in the glycoside hydrolase family 130 (GH130, CAZy database) have been proposed to perform the phosphorolysis of β-1,2 and β-1,4-mannosyl linkages between the mannose at the non-reducing end of substrates and mannose, glucose or N-acetylglucosamine residues, with the subsequent release of α-mannose-1-phosphate. In this study, we compare five different GH130 enzymes (CpMan130 A-E) encoded within the genome of Caldanaerobius polysaccharolyticus, a thermophilic anaerobic bacterium able to ferment mannan as the sole carbon source.Analysis of substrate specificity and end product release allowed for the identification of pathways involving GH130 enzymes in the metabolism of mannans with different structures by this organism. Mechanistic studies involving the binding order and amino acid mapping on a three-dimensional model of Man130B helped to elucidate the ordered sequential bi-bi mechanism utilized by these enzymes. Phylogenetic analysis of over 950 sequences assigned to the GH130 family, combined with differences in amino acid conservation and substrate specificity, revealed a new subgroup for this family, GH130_3, consisting of thermostable enzymes that act on β-1,2-linked manno-oligosaccharides. The genomic context of all genes in the proposed subgroup GH130_3 suggests that they appear in pairs, preceded by an ABC-like transporter.