Rapid internal dynamics of BPTI is insensitive to pressure

FEBS Letters

Li, Hua²  Yamada, Hiroaki³  Woodward, Clare K.¹  Sareth, Sina²  Akasaka, Kazuyuki² 

[1] Department of Biochemistry, University of Minnesota, St.-Paul, MN 55108, USA;Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan;Department of Chemistry, Faculty of Science, Kobe University, Kobe 657-8501, Japan

关键词: High pressure nuclear magnetic resonance;    Basic pancreatic trypsin inhibitor;    15N spin relaxation;    Chemical shift;    Internal dynamics;   

DOI  :  10.1016/S0014-5793(00)01283-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Pressure effects on the backbone dynamics of a native basic pancreatic trypsin inhibitor (BPTI) have been measured by ¹⁵N spin relaxation and chemical shifts at 30 and 2000 bar. The experiments utilized the on-line variable pressure cell nuclear magnetic resonance system on ¹⁵N-uniformly labeled BPTI at a proton frequency of 750.13 MHz at 36°C. Longitudinal (R ₁) and transverse (R ₂) ¹⁵N relaxation times and (¹H)–¹⁵N nuclear Overhauser effects were measured for 41 protonated backbone nitrogens at both pressures. The model free analysis of the internal dynamics gave order parameters for individual H–N vectors at both pressures. The results indicate that rapid internal dynamics in the ps–ns range for the polypeptide backbone is not significantly affected by pressure in the range between 30 bar and 2 kbar. The result is consistent with the linear pressure dependence of ¹H and ¹⁵N chemical shifts of BPTI, which suggests that local compressibilities and amplitudes of associated conformational fluctuation are nearly invariant in the same pressure range. Overall, we conclude that at 2 kbar BPTI remains within the same native ensemble as at 1 bar, with a small shift of population from that at 1 bar.

【 授权许可】

Unknown