3rdk
From Proteopedia
Protein crystal structure of xylanase A1 of Paenibacillus sp. JDR-2
Structural highlights
Function[XYNA1_PAESJ] Catalyzes the depolymerization of methylglucuronoxylan (MeGAXn), a beta-1,4 xylan in which 10% to 20% of the xylose residues are substituted with alpha-1,2-4-O-methylglucuronate (MeGA) residues, which is predominant in hemicellulose fractions of hardwood and crop residues. Generates xylobiose (X2) and aldotetrauronate (MeGAX3) as the predominant products of MeGAXn hydrolysis; these products are then directly assimilated by the bacterium for subsequent metabolism. Thus, allows the bacterium to efficiently use polymeric MeGAXn as a growth substrate.[1] Publication Abstract from PubMedThe Gram-positive bacterium Paenibacillus sp. JDR-2 (PbJDR2) has been shown to have novel properties in the utilization of the abundant but chemically complex hemicellulosic sugar glucuronoxylan. Xylanase A1 of PbJDR2 (PbXynA1) has been implicated in an efficient process in which extracellular depolymerization of this polysaccharide is coupled to assimilation and intracellular metabolism. PbXynA1is a 154kDa cell wall anchored multimodular glycosyl hydrolase family 10 (GH10) xylanase. In this work, the 38kDa catalytic module of PbXynA1 has been structurally characterized revealing several new features not previously observed in structures of GH10 xylanases. These features are thought to facilitate hydrolysis of highly substituted, chemically complex xylans that may be the form found in close proximity to the cell wall of PbJDR2, an organism shown to have a preference for growth on polymeric glucuronoxylan. Novel structural features of xylanase A1 from Paenibacillus sp. JDR-2.,St John FJ, Preston JF, Pozharski E J Struct Biol. 2012 Sep 18. pii: S1047-8477(12)00249-3. doi:, 10.1016/j.jsb.2012.09.007. PMID:23000703[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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