Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.16 (HIV-1 protease)
 2,107 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Relaxation compensated constant-time Carr-Purcell-Meiboom-Gill relaxation dispersion experiments for amide protons are presented that detect mus-ms time-scale dynamics of protein backbone amide sites. Because of their ten-fold larger magnetogyric ratio, much shorter 180 degrees pulses can be applied to (1)H than to (15)N spins; therefore, off-resonance effects are reduced and a wider range of effective rf fields can often be used in the case of (1)H experiments. Applications to [(1)H-(15)N]-ubiquitin and [(1)H-(15)N]-perdeuterated HIV-1 protease are discussed. In the case of ubiquitin, we present a pulse sequence that reduces artifacts that arise from homonuclear (3)J(H(N)-H(alpha)) coupling. In the case of the protease, we show that relaxation dispersion of both (1)H and (15)N spins provides a more comprehensive picture of slow backbone dynamics than does the relaxation dispersion of either spin alone. We also compare the relative merits of (1)H versus (15)N transverse relaxation measurements and note the benefits of using a perdeuterated protein to measure the relaxation dispersion of both spin types.
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PMID:Extending the range of amide proton relaxation dispersion experiments in proteins using a constant-time relaxation-compensated CPMG approach. 1265 36

HNN has proven to be an extremely valuable experiment for rapid and unambiguous backbone (H(N), (15)N) assignment in ((13)C, (15)N) labeled proteins. However, low sensitivity of the experiment is often a limiting factor, especially when the transverse relaxation times (T(2)) are short. We show here that BEST modification Schanda et al. (2006) [2] increases the sensitivity per unit time by more than a factor of 2.0 and thus substantially increases the speed of data collection; good 3D data can be collected in 8-10h. Next, we present a simple method for amino-acid type identification based on simple 2D versions of the HNN experiment, labeled here as 2D-(HN)NH. Each of these experiments which produce anchor points for Gly, Ala, Ser/Thr residues, can be recorded in less than an hour. These enable rapid data acquisition, rapid analysis, and consequently rapid assignment of backbone (H(N), (15)N) resonances. The 2D-(HN)NH experiment does not involve aliphatic/aromatic protons and hence can be applied to deuterated protein samples as well, which is an additional advantage. The experiments have been demonstrated with human ubiquitin (76 aa) and acetic-acid denatured HIV-1 protease (99 aa), as representatives of folded and unfolded protein systems, respectively.
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PMID:BEST-HNN and 2D-(HN)NH experiments for rapid backbone assignment in proteins. 2023 46