2ou8
From Proteopedia
Structure of Spin-labeled T4 Lysozyme Mutant T115R1 at Room Temperature
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 PubMedA nitroxide side chain (R1) has been substituted at single sites along a helix-turn-helix motif in T4 lysozyme (residues 114-135). Together with previously published data, the new sites reported complete a continuous scan through the motif. Mutants with R1 at sites 115 and 118 were selected for crystallographic analysis to identify the structural origins of the corresponding two-component EPR spectra. At 115, R1 is shown to occupy two rotamers in the room temperature crystal structure, one of which has not been previously reported. The two components in the EPR spectrum apparently arise from differential interactions of the two rotamers with the surrounding structure, the most important of which is a hydrophobic interaction of the nitroxide ring. Interestingly, the crystal structure at 100 K reveals a single rotamer, emphasizing the possibility of rotamer selection in low-temperature crystal structures. Residue 118 is at a solvent-inaccessible site in the protein core, and the structure of 118R1, the first reported for the R1 side chain at a buried site, reveals how the side chain is accommodated in an overpacked core. Structural determinants of nitroxide motion in spin-labeled proteins: tertiary contact and solvent-inaccessible sites in helix G of T4 lysozyme.,Guo Z, Cascio D, Hideg K, Kalai T, Hubbell WL Protein Sci. 2007 Jun;16(6):1069-86. Epub 2007 May 1. PMID:17473014[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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