2agm
From Proteopedia
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Solution structure of the R-module from AlgE4
Overview
In the bacterium Azotobacter vinelandii, a family of seven secreted and, calcium-dependent mannuronan C-5 epimerases (AlgE1-7) has been identified., These epimerases are responsible for the epimerization of, beta-d-mannuronic acid to alpha-l-guluronic acid in alginate polymers. The, epimerases consist of two types of structural modules, designated A (one, or two copies) and R (one to seven copies). The structure of the, catalytically active A-module from the smallest epimerase AlgE4, (consisting of AR) has been solved recently. This paper describes the NMR, structure of the R-module from AlgE4 and its titration with a substrate, analogue and paramagnetic thulium ions. The R-module folds into a, right-handed parallel beta-roll. The overall shape of the R-module is an, elongated molecule with a positively charged patch that interacts with the, substrate. Titration of the R-module with thulium indicated possible, calcium binding sites in the loops formed by the nonarepeat sequences in, the N-terminal part of the molecule and the importance of calcium binding, for the stability of the R-module. Structure calculations showed that, calcium ions can be incorporated in these loops without structural, violations and changes. Based on the structure and the electrostatic, surface potential of both the A- and R-module from AlgE4, a model for the, appearance of the whole protein is proposed.
About this Structure
2AGM is a Single protein structure of sequence from Azotobacter vinelandii. Full crystallographic information is available from OCA.
Reference
NMR structure of the R-module: a parallel beta-roll subunit from an Azotobacter vinelandii mannuronan C-5 epimerase., Aachmann FL, Svanem BI, Guntert P, Petersen SB, Valla S, Wimmer R, J Biol Chem. 2006 Mar 17;281(11):7350-6. Epub 2006 Jan 3. PMID:16407237
Page seeded by OCA on Wed Nov 21 08:06:38 2007
