8thn

KcsA M96V mutant with Y78ester in High K+

spinqualitylabelsall models 8thn, resolution 2.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8thn is a 3 chain structure with sequence from Mus musculus and Streptomyces lividans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.9Å Ligands: K, TBA, TYF Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function KCSA_STRLI Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+). Publication Abstract from PubMed Amide-to-ester substitutions are used to study the role of the amide bonds of the protein backbone in protein structure, function, and folding. An amber suppressor tRNA/synthetase pair has been reported for incorporation of p-hydroxy-phenyl-L-lactic acid (HPLA), thereby introducing ester substitution at tyrosine residues. However, the application of this approach was limited due to the low yields of the modified proteins and the high cost of HPLA. Here we report the in vivo generation of HPLA from the significantly cheaper phenyl-L-lactic acid. We also construct an optimized plasmid with the HPLA suppressor tRNA/synthetase pair that provides higher yields of the modified proteins. The combination of the new plasmid and the in-situ generation of HPLA provides a facile and economical approach for introducing tyrosine ester substitutions. We demonstrate the utility of this approach by introducing tyrosine ester substitutions into the K(+) channel KcsA and the integral membrane enzyme GlpG. We introduce the tyrosine ester in the selectivity filter of the M96V mutant of the KcsA to probe the role of the second ion binding site in the conformation of the selectivity filter and the process of inactivation. We use tyrosine ester substitutions in GlpG to perturb backbone H-bonds to investigate the contribution of these H-bonds to membrane protein stability. We anticipate that the approach developed in this study will facilitate further investigations using tyrosine ester substitutions. A facile approach for incorporating tyrosine esters to probe ion-binding sites and backbone hydrogen bonds.,Reddi R, Chatterjee S, Matulef K, Gustafson A, Gao L, Valiyaveetil FI J Biol Chem. 2023 Nov 30;300(1):105517. doi: 10.1016/j.jbc.2023.105517. PMID:38042487 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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