3hwl
Crystal Structure of T4 lysozyme with the unnatural amino acid p-Acetyl-L-Phenylalanine incorporated at position 131
Structural highlights
FunctionENLYS_BPT4 Endolysin with lysozyme activity that degrades host peptidoglycans and participates with the holin and spanin proteins in the sequential events which lead to the programmed host cell lysis releasing the mature viral particles. Once the holin has permeabilized the host cell membrane, the endolysin can reach the periplasm and break down the peptidoglycan layer.[1] 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 PubMedThe traditional site-directed spin labeling (SDSL) method, which utilizes cysteine residues and sulfhydryl-reactive nitroxide reagents, can be challenging for proteins that contain functionally important native cysteine residues or disulfide bonds. To make SDSL amenable to any protein, we introduce an orthogonal labeling strategy, i.e., one that does not rely on any of the functional groups found in the common 20 amino acids. In this method, the genetically encoded unnatural amino acid p-acetyl-L-phenylalanine (p-AcPhe) is reacted with a hydroxylamine reagent to generate a nitroxide side chain (K1). The utility of this scheme was demonstrated with seven mutants of T4 lysozyme, each containing a single p-AcPhe at a solvent-exposed helix site; the mutants were expressed in amounts qualitatively similar to the wild-type protein. In general, the EPR spectra of the resulting K1 mutants reflect higher nitroxide mobilities than the spectra of analogous mutants containing the more constrained disulfide-linked side chain (R1) commonly used in SDSL. Despite this increased flexibility, site dependence of the EPR spectra suggests that K1 will be a useful sensor of local structure and of conformational changes in solution. Distance measurements between pairs of K1 residues using double electron electron resonance (DEER) spectroscopy indicate that K1 will also be useful for distance mapping. Site-directed spin labeling of a genetically encoded unnatural amino acid.,Fleissner MR, Brustad EM, Kalai T, Altenbach C, Cascio D, Peters FB, Hideg K, Peuker S, Schultz PG, Hubbell WL Proc Natl Acad Sci U S A. 2009 Dec 22;106(51):21637-42. Epub 2009 Dec 7. PMID:19995976[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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