1e5j: Difference between revisions
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==Overview== | ==Overview== | ||
A new class of inhibitors for beta-D-glycoside hydrolases, in which a, single alpha-(1-->4)-glycosidic bond is incorporated into an otherwise, all-beta-(1-->4)-linked oligosaccharide, is described. Such mixed, beta/alpha-linkage cellooligosaccharides are not transition-state mimics, but instead are capable of utilising binding energy from numerous, subsites, spanning either side of the catalytic centre, without the need, for substrate distortion. This binding is significant; a mixed, alpha/beta-D-tetrasaccharide acts competitively on a number of cellulases, displaying inhibition constants in the range of 40-300 microM. Using the, Bacillus agaradhaerens enzyme Cel5A as a model system, one such mixed, beta/alpha-cellooligosaccharide, methyl, ... | A new class of inhibitors for beta-D-glycoside hydrolases, in which a, single alpha-(1-->4)-glycosidic bond is incorporated into an otherwise, all-beta-(1-->4)-linked oligosaccharide, is described. Such mixed, beta/alpha-linkage cellooligosaccharides are not transition-state mimics, but instead are capable of utilising binding energy from numerous, subsites, spanning either side of the catalytic centre, without the need, for substrate distortion. This binding is significant; a mixed, alpha/beta-D-tetrasaccharide acts competitively on a number of cellulases, displaying inhibition constants in the range of 40-300 microM. Using the, Bacillus agaradhaerens enzyme Cel5A as a model system, one such mixed, beta/alpha-cellooligosaccharide, methyl, 4(II),4(III)-dithio-alpha-cellobiosyl-(1-->4)-beta-cellobioside, displays, a K(i) value of 100 microM, an inhibition at least 150 times better than, is observed with an equivalent all-beta-linked compound. The, three-dimensional structure of B. agaradhaerens Cel5A in complex with, methyl 4(II),4(III)-dithio-alpha-cellobiosyl-(1-->4)-beta-cellobioside has, been determined at 1.8 A resolution. This confirms the expected mode of, binding in which the ligand, with all four pyranosides in the (4)C(1), chair conformation, occupies the -3, -2 and +1 subsites whilst evading the, catalytic (-1) subsite. Such "by-pass" compounds offer great scope for the, development of a new class of beta-D-glycoside hydrolase inhibitors. | ||
==About this Structure== | ==About this Structure== | ||
1E5J is a | 1E5J is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_agaradhaerens Bacillus agaradhaerens] with GLC, SGC and CA as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Structure known Active Site: ACI. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1E5J OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:49:32 2007'' | ||
