2brw: Difference between revisions

Streptococcus pneumoniae hyaluronan lyase is a surface enzyme of this, Gram-positive bacterium. The enzyme degrades several biologically, important, information-rich linear polymeric glycans: hyaluronan, unsulfated chondroitin, and some chondroitin sulfates. This degradation, facilitates spreading of bacteria throughout the host tissues and, presumably provides energy and a carbon source for pneumococcal cells. Its, beta-elimination catalytic mechanism is an acid/base process termed proton, acceptance and donation leading to cleavage of beta-1,4 linkages of the, substrates. The degradation of hyaluronan occurs in two stages, initial, endolytic cuts are followed by processive exolytic cleavage of one, disaccharide at a time. In contrast, the degradation of chondroitins is, purely endolytic. Structural studies together with flexibility analyses of, two streptococcal enzymes, from S.pneumoniae and Streptococcus agalactiae, allowed for insights into this enzyme's molecular mechanism. Here, two new, X-ray crystal structures of the pneumococcal enzyme in novel conformations, are reported. These new conformations, complemented by molecular dynamics, simulation results, directly confirm the predicted domain motions presumed, to facilitate the processive degradative process. One of these new, structures resembles the S.agalactiae enzyme conformation, and provides, evidence of a uniform mechanistic/dynamic behavior of this protein across, different bacteria.

2BRW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pneumoniae Streptococcus pneumoniae] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Hyaluronate_lyase Hyaluronate lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.2.1 4.2.2.1] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BRW OCA].  

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