1ZYT
Crystal structure of spin labeled T4 Lysozyme (A82R1)
Summary for 1ZYT
| Entry DOI | 10.2210/pdb1zyt/pdb |
| Related | 2CUU |
| Descriptor | Lysozyme, S-[(1-oxyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-3-yl)methyl] methanesulfonothioate, AZIDE ION, ... (6 entities in total) |
| Functional Keywords | nitroxide spin label, modified cysteine, hydrolase |
| Biological source | Enterobacteria phage T4 |
| Total number of polymer chains | 1 |
| Total formula weight | 19227.44 |
| Authors | Fleissner, M.R.,Cascio, D.,Sawaya, M.R.,Hideg, K.,Hubbell, W.L. (deposition date: 2005-06-10, release date: 2006-08-15, Last modification date: 2024-10-30) |
| Primary citation | Fleissner, M.R.,Cascio, D.,Hubbell, W.L. Structural origin of weakly ordered nitroxide motion in spin-labeled proteins Protein Sci., 18:893-908, 2009 Cited by PubMed Abstract: A disulfide-linked nitroxide side chain (R1) used in site-directed spin labeling of proteins often exhibits an EPR spectrum characteristic of a weakly ordered z-axis anisotropic motion at topographically diverse surface sites, including those on helices, loops and edge strands of beta-sheets. To elucidate the origin of this motion, the first crystal structures of R1 that display simple z-axis anisotropic motion at solvent-exposed helical sites (131 and 151) and a loop site (82) in T4 lysozyme have been determined. Structures of 131R1 and 151R1 determined at cryogenic or ambient temperature reveal an intraresidue C(alpha)--H...S(delta) interaction that immobilizes the disulfide group, consistent with a model in which the internal motions of R1 are dominated by rotations about the two terminal bonds (Columbus, Kálai, Jeko, Hideg, and Hubbell, Biochemistry 2001;40:3828-3846). Remarkably, the 131R1 side chain populates two rotamers equally, but the EPR spectrum reflects a single dominant dynamic population, showing that the two rotamers have similar internal motion determined by the common disulfide-backbone interaction. The anisotropic motion for loop residue 82R1 is also accounted for by a common disulfide-backbone interaction, showing that the interaction does not require a specific secondary structure. If the above observations prove to be general, then significant variations in order and rate for R1 at noninteracting solvent-exposed helical and loop sites can be assigned to backbone motion because the internal motion is essentially constant. PubMed: 19384990DOI: 10.1002/pro.96 PDB entries with the same primary citation |
| Experimental method | EPR X-RAY DIFFRACTION (1.7 Å) |
Structure validation
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