3f45 | pdb_00003f45

Structure of the R75A mutant of rat alpha-Parvalbumin

spinqualitylabelsall models 3f45, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3f45 is a 1 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, SO4 Gene: Pvalb, Pva (Rattus norvegicus) Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Parvalbumins (PVs) are calcium-buffer proteins that belong to the EF-hand family. Their N-terminal domain consists of two antiparallel helices A and B that make up a flat hydrophobic surface that is associated with the opposite side of the CD and EF binding sites. A single conserved Arg75-Glu81 salt bridge is buried in this hydrophobic interface. The structure of a rat PV mutant in which Arg75 was replaced by alanine was solved by molecular replacement. Unexpectedly, a large distance deviation of 7.8 A was observed for the AB loop but not for the residues that flank the R75A mutation. The thermal stability of the calcium-loaded form is lower (T(m) = 352.0 K; DeltaT(m) = -11.4 K) than that of the wild-type protein and the apo mutant is unfolded at room temperature. Weaker calcium or magnesium affinities were also measured for the R75A mutant (Ca(2+): K(1) = 4.21 x 10(7) M(-1), K(2) = 6.18 x 10(6) M(-1); Mg(2+): K(1) = 2.98 x 10(4) M(-1), K(2) = 3.09 x 10(3) M(-1)). Finally, comparison of the B factors showed an increase in the flexibility of the AB loop that is consistent with this region being more exposed to solvent in the mutant. The mutant structure therefore demonstrates the role of the salt bridge in attaching the nonbinding AB domain to the remaining protein core. Normal-mode analysis indeed indicated an altered orientation of the AB domain with regard to the CD-EF binding domains. Removing the invariant salt bridge of parvalbumin increases flexibility in the AB-loop structure.,Hoh F, Cave A, Strub MP, Baneres JL, Padilla A Acta Crystallogr D Biol Crystallogr. 2009 Aug;65(Pt 8):733-43. Epub 2009, Jul 10. PMID:19622856 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Parvalbumin

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