Conformational Entropy from Slowly Relaxing Local Structure Analysis of N-15-H Relaxation in Proteins: Application to Pheromone Binding to MUP-I in the 283-308 K Temperature Range

ŽÍDEK, Lukáš and Eva MEIROVITCH. Conformational Entropy from Slowly Relaxing Local Structure Analysis of N-15-H Relaxation in Proteins: Application to Pheromone Binding to MUP-I in the 283-308 K Temperature Range. Journal of Physical Chemistry B. WASHINGTON: AMER CHEMICAL SOC, 2017, vol. 121, No 37, p. 8684-8692. ISSN 1520-6106. Available from: https://dx.doi.org/10.1021/acs.jpcb.7b06049.

Basic information

• Original name: Conformational Entropy from Slowly Relaxing Local Structure Analysis of N-15-H Relaxation in Proteins: Application to Pheromone Binding to MUP-I in the 283-308 K Temperature Range
• Authors: ŽÍDEK, Lukáš (203 Czech Republic, guarantor, belonging to the institution) and Eva MEIROVITCH (376 Israel).
• Edition: Journal of Physical Chemistry B, WASHINGTON, AMER CHEMICAL SOC, 2017, 1520-6106.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10403 Physical chemistry
• Country of publisher: United States of America
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 3.146
• RIV identification code: RIV/00216224:14310/17:00098087
• Organization unit: Faculty of Science
• Doi: http://dx.doi.org/10.1021/acs.jpcb.7b06049
• UT WoS: 000411772100007
• Keywords in English: MODEL-FREE APPROACH; MAGNETIC-RESONANCE RELAXATION; NMR RELAXATION; BACKBONE DYNAMICS; LIGAND-BINDING; ORDER PARAMETERS; DEPENDENCE; COMPLEX; DOMAIN; MOTIONS
• Tags: NZ, rivok
• Tags: International impact, Reviewed

Abstract

The slowly relaxing local structure (SRLS) approach is applied to N-15-H relaxation from the major urinary protein I (MUP-I), and its complex with pheromone 2-sec-butyl-4,5-dihydrothiazol. The objective is to elucidate dynamics, and binding-induced changes in conformational entropy. Experimental data acquired previously in the 283- 308 K temperature range are used. The N-H bond is found to reorient globally with correlation time, tau(1,0) and locally with correlation time, tau(2,0), where tau(1,0) >> tau(2,0). The local motion is restricted by the potential u =-c(0)(2)D(00)(2), where D-00(2) is the Wigner rotation matrix element for L = 2, K = 0, and c(0)(2) evaluates the strength of the potential. u yields straightforwardly the order parameter, < D-00(2)>, and the conformational entropy, S-k, both given by P-eq = exp(-u). The deviation of the local ordering/local diffusion axis from the N-H bond, given by the angle beta, is also determined. We find that c(0)(2) congruent to 18 +/- 4 and T-2,T-0 = 0-170 ps for ligand-free MUP-I, whereas c(0)(2) congruent to 15 +/- 4 and tau(2,0) = 20-270 ps for ligand-bound MUP-I beta is in the 0-10 degrees range. c(0)(2) and tau(2,0) decrease, whereas beta increases, when the temperature is increased from 283 to 308 K. Thus, SRLS provides physically well-defined structure-related (c(0)(2) and < D-00 >(2)), motion-related (tau(2,0)), geometry related (beta), and binding-related (S-k) local parameters, and their temperature-dependences. Intriguingly, upon pheromone binding the conformational entropy of MUP-I decreases at high temperature and increases at low temperature. The very same experimental data were analyzed previously with the model-free (MF) method which yielded "global" (in this context, "relating to the entire 283-308 K range") amplitude (S-2) and rate (tau(e)) of the local motion, and a phenomenological exchange term (R-ex). S-2 is found to decrease (implying implicitly "global" increase in S-k) upon pheromone binding.