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Two-dimensional NMR studies of staphylococcal nuclease. 2. Sequence-specific assignments of carbon-13 and nitrogen-15 signals from the nuclease H124L-thymidine 3 prime ,5 prime -bisphosphate-Ca sup 2+ ternary complex

Journal Article · · Biochemistry; (USA)
DOI:https://doi.org/10.1021/bi00453a012· OSTI ID:6827583

Samples of staphylococcal nuclease H124L (cloned protein overproduced in Escherichia coli whose sequence is identical with that of the nuclease isolated from the V8 strain of Staphylococcus aureus) were labeled uniformly with carbon-13 (26% ul {sup 13}C), uniformly with nitrogen-15 (95% ul {sup 15}N), and specifically by incorporating nitrogen-15-labeled leucine ((98% {sup 15}N)Leu) or carbon-13-labeled lysine ((26% ul {sup 13}C)Lys), arginine ((26% ul {sup 13}C)Arg), or methionine ((26% ul {sup 13}C)Met). Solutions of the ternary complexes of these analogues (nuclease H124L-pdTp-Ca{sup 2+}) at pH 5.1 (H{sub 2}O) or pH 5.5 ({sup 2}H{sub 2}O) at 45{degree}C were analyzed as appropriate to the labeling pattern by multinuclear two-dimensional (2D) NMR experiments spectrometer fields of 14.09 and 11.74 T. The results have assisted in spin system assignments and in identification of secondary structural elements. Nuclear Overhauser enhancements (NOE's) characteristic of antiparellel {beta}-sheet (d{sub {alpha}{alpha} }NOE's) were observed in the {sup 1}H({sup 13}C)-SBC-NOE spectrum of the nuclease ternary complex labeled uniformly with {sup 13}C. NOE's characteristic of {alpha}-helix were observed in the {sup 1}H({sup 15}N)SBC-NOE spectrum of the complex prepared from protein labeled uniformly with {sup 15}N. The assignments obtained from these multinuclear NMR studies have confirmed and extended assignments based on {sup 1}H({sup 1}H) 2D NMR experiments.

OSTI ID:
6827583
Journal Information:
Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:1; ISSN 0006-2960; ISSN BICHA
Country of Publication:
United States
Language:
English