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PDBsum entry 3xim

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Isomerase(intramolecular oxidoreductse) PDB id
3xim
Jmol
Contents
Protein chains
391 a.a. *
Ligands
SOR ×4
Metals
_CO ×8
Waters ×871
* Residue conservation analysis

References listed in PDB file
Key reference
Title Arginine residues as stabilizing elements in proteins.
Authors N.T.Mrabet, A.Van den broeck, I.Van den brande, P.Stanssens, Y.Laroche, A.M.Lambeir, G.Matthijssens, J.Jenkins, M.Chiadmi, H.Van tilbeurgh.
Ref. Biochemistry, 1992, 31, 2239-2253. [DOI no: 10.1021/bi00123a005]
PubMed id 1540579
Abstract
Site-specific substitutions of arginine for lysine in the thermostable D-xylose isomerase (XI) from Actinoplanes missouriensis are shown to impart significant heat stability enhancement in the presence of sugar substrates most probably by interfering with nonenzymatic glycation. The same substitutions are also found to increase heat stability in the absence of any sugar derivatives, where a mechanism based on prevention of glycation can no longer be invoked. This rather conservative substitution is moreover shown to improve thermostability in two other structurally unrelated proteins, human copper, zinc-superoxide dismutase (CuZnSOD) and D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Bacillus subtilis. The stabilizing effect of Lys----Arg substitutions is rationalized on the basis of a detailed analysis of the crystal structures of wild-type XI and of engineered variants with Lys----Arg substitution at four distinct locations, residues 253, 309, 319, and 323. Molecular model building analysis of the structures of wild-type and mutant CuZnSOD (K9R) and GAPDH (G281K and G281R) is used to explain the observed stability enhancement in these proteins. In addition to demonstrating that even thermostable proteins can lend themselves to further stability improvement, our findings provide direct evidence that arginine residues are important stabilizing elements in proteins. Moreover, the stabilizing role of electrostatic interactions, particularly between subunits in oligomeric proteins, is documented.
Secondary reference #1
Title Structural analysis of the 2.8 a model of xylose isomerase from actinoplanes missouriensis.
Authors F.Rey, J.Jenkins, J.Janin, I.Lasters, P.Alard, M.Claessens, G.Matthyssens, S.Wodak.
Ref. Proteins, 1988, 4, 165-172.
PubMed id 3237716
Abstract
PROCHECK
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 Headers