1nn4

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spinqualitylabelsall models 1nn4, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structural Genomics, RpiB/AlsB

Overview

Ribose-5-phosphate isomerases (EC 5.3.1.6) interconvert ribose 5-phosphate, and ribulose 5-phosphate. This reaction permits the synthesis of ribose, from other sugars, as well as the recycling of sugars from nucleotide, breakdown. Two unrelated types of enzyme can catalyze the reaction. The, most common, RpiA, is present in almost all organisms (including, Escherichia coli), and is highly conserved. The second type, RpiB, is, present in some bacterial and eukaryotic species and is well conserved. In, E.coli, RpiB is sometimes referred to as AlsB, because it can take part in, the metabolism of the rare sugar, allose, as well as the much more common, ribose sugars. We report here the structure of RpiB/AlsB from E.coli, solved by multi-wavelength anomalous diffraction (MAD) phasing, and, refined to 2.2A resolution. RpiB is the first structure to be solved from, pfam02502 (the RpiB/LacAB family). It exhibits a Rossmann-type, alphabetaalpha-sandwich fold that is common to many nucleotide-binding, proteins, as well as other proteins with different functions. This, structure is quite distinct from that of the previously solved RpiA;, although both are, to some extent, based on the Rossmann fold, their, tertiary and quaternary structures are very different. The four molecules, in the RpiB asymmetric unit represent a dimer of dimers. Active-site, residues were identified at the interface between the subunits, such that, each active site has contributions from both subunits. Kinetic studies, indicate that RpiB is nearly as efficient as RpiA, despite its completely, different catalytic machinery. The sequence and structural results further, suggest that the two homologous components of LacAB (galactose-6-phosphate, isomerase) will compose a bi-functional enzyme; the second activity is, unknown.

About this Structure

1NN4 is a Single protein structure of sequence from Escherichia coli. Active as Ribose-5-phosphate isomerase, with EC number 5.3.1.6 Full crystallographic information is available from OCA.

Reference

The 2.2 A resolution structure of RpiB/AlsB from Escherichia coli illustrates a new approach to the ribose-5-phosphate isomerase reaction., Zhang RG, Andersson CE, Skarina T, Evdokimova E, Edwards AM, Joachimiak A, Savchenko A, Mowbray SL, J Mol Biol. 2003 Oct 3;332(5):1083-94. PMID:14499611

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