Document Detail


Measuring rapid hydrogen exchange in the homodimeric 36 kDa HIV-1 integrase catalytic core domain.
MedLine Citation:
PMID:  21213249     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Measurements of rapid hydrogen exchange (HX) of water with protein amide sites contain valuable information on protein structure and function, but current NMR methods for measuring HX rates are limited in their applicability to large protein systems. An alternate method for measuring rapid HX is presented that is well-suited for larger proteins, and we apply the method to the deuterated, homodimeric 36 kDa HIV-1 integrase catalytic core domain (CCD). Using long mixing times for water-amide magnetization exchange at multiple pH values, HX rates spanning more than four orders of magnitude were measured, as well as NOE cross-relaxation rates to nearby exchangeable protons. HX protection factors for the CCD are found to be large (>10(4)) for residues along the dimer interface, but much smaller in many other regions. Notably, the catalytic helix (residues 152-167) exhibits low HX protection at both ends, indicative of fraying at both termini as opposed to just the N-terminal end, as originally thought. Residues in the LEDGF/p75 binding pocket also show marginal stability, with protection factors in the 10-100 range (∼1.4-2.7 kcal/mol). Additionally, elevated NOE cross-relaxation rates are identified and, as expected, correspond to proximity of the amide proton to a rapidly exchanging proton, typically from an OH side chain. Indirect NOE transfer between H(2) O and the amide proton of I141, a residue in the partially disordered active site of the enzyme, suggests its proximity to the side chain of S147, an interaction seen in the DNA-bound form for a homologous integrase.
Authors:
Nicholas C Fitzkee; Dennis A Torchia; Ad Bax
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural     Date:  2011-02-17
Journal Detail:
Title:  Protein science : a publication of the Protein Society     Volume:  20     ISSN:  1469-896X     ISO Abbreviation:  Protein Sci.     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-03-24     Completed Date:  2011-07-14     Revised Date:  2013-07-03    
Medline Journal Info:
Nlm Unique ID:  9211750     Medline TA:  Protein Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  500-12     Citation Subset:  IM    
Copyright Information:
Copyright © 2011 The Protein Society.
Affiliation:
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
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MeSH Terms
Descriptor/Qualifier:
Catalytic Domain*
HIV Integrase / chemistry*,  metabolism*
Humans
Hydrogen / chemistry,  metabolism*
Models, Molecular
Nuclear Magnetic Resonance, Biomolecular
Protein Structure, Tertiary*
Chemical
Reg. No./Substance:
0/p31 integrase protein, Human immunodeficiency virus 1; 1333-74-0/Hydrogen; EC 2.7.7.-/HIV Integrase
Comments/Corrections
Erratum In:
Protein Sci. 2011 Sep;20(9):1643

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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