4p5s

Structure of reduced W45Y mutant of amicyanin

spinqualitylabelsall models 4p5s, resolution 1.02Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4p5s is a 1 chain structure with sequence from Atcc 17741. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CU1 Related: 4p5r Gene: mauC, ami (ATCC 17741) Resources: FirstGlance, OCA, RCSB, PDBsum Function [AMCY_PARDE] Primary acceptor of electrons from methylamine dehydrogenase. Passes those electrons on either a soluble cytochrome c or to pseudoazurin. Publication Abstract from PubMed The cupredoxin amicyanin possesses a single tryptophan residue, Trp45. Its fluorescence is quenched when copper is bound even though it separated by 10.1A. Mutation of Trp45 to Ala, Phe, Leu and Lys resulted in undetectable protein expression. A W45Y amicyanin variant was isolated. The W45Y mutation did not alter the spectroscopic properties or intrinsic redox potential of amicyanin, but increased the pKa value for the pH-dependent redox potential by 0.5units. This is due to a hydrogen-bond involving the His95 copper ligand which is present in reduced W45Y amicyanin but not in native amicyanin. The W45Y mutation significantly decreased the thermal stability of amicyanin, as determined by changes in the visible absorbance of oxidized amicyanin and in the circular dichroism spectra for oxidized, reduced and apo forms of amicyanin. Comparison of the crystal structures suggests that the decreased stability of W45Y amicyanin may be attributed to the loss of a strong interior hydrogen bond between Trp45 and Tyr90 in native amicyanin which links two of the beta-sheets that comprise the overall structure of amicyanin. Thus, Trp45 is critical for stabilizing the structure of amicyanin but it does not influence the electronic properties of the copper which quenches its fluorescence. The sole tryptophan of amicyanin enhances its thermal stability but does not influence the electronic properties of the type 1 copper site.,Dow BA, Sukumar N, Matos JO, Choi M, Schulte A, Tatulian SA, Davidson VL Arch Biochem Biophys. 2014 Apr 1. pii: S0003-9861(14)00111-8. doi:, 10.1016/j.abb.2014.03.010. PMID:24704124 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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