skip to main content

Title: Infrared Protein Crystallography

We consider the application of infrared spectroscopy to protein crystals, with particular emphasis on exploiting molecular orientation through polarization measurements on oriented single crystals. Infrared microscopes enable transmission measurements on individual crystals using either thermal or nonthermal sources, and can accommodate flow cells, used to measure spectral changes induced by exposure to soluble ligands, and cryostreams, used for measurements of flash-cooled crystals. Comparison of unpolarized infrared measurements on crystals and solutions probes the effects of crystallization and can enhance the value of the structural models refined from X-ray diffraction data by establishing solution conditions under which they are most relevant. Results on several proteins are consistent with similar equilibrium conformational distributions in crystal and solutions. However, the rates of conformational change are often perturbed. Infrared measurements also detect products generated by X-ray exposure, including CO{sub 2}. Crystals with favorable symmetry exhibit infrared dichroism that enhances the synergy with X-ray crystallography. Polarized infrared measurements on crystals can distinguish spectral contributions from chemically similar sites, identify hydrogen bonding partners, and, in opportune situations, determine three-dimensional orientations of molecular groups. This article is part of a Special Issue entitled: Protein Structure and Function in the Crystalline State.
Authors:
; ; ; ; ;
Publication Date:
OSTI Identifier:
1041645
Report Number(s):
BNL-97323-2012-JA
Journal ID: ISSN 0006-3002; BBACAQ; TRN: US201212%%63
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochimica et Biophysica Acta; Journal Volume: 1814; Journal Issue: 6
Research Org:
BROOKHAVEN NATIONAL LABORATORY (BNL)
Sponsoring Org:
USDOE SC OFFICE OF SCIENCE (SC)
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; BONDING; CONFORMATIONAL CHANGES; CRYSTALLIZATION; CRYSTALLOGRAPHY; DICHROISM; HYDROGEN; MICROSCOPES; MONOCRYSTALS; ORIENTATION; POLARIZATION; PROBES; PROTEIN STRUCTURE; PROTEINS; RADIATIONS; SPECTROSCOPY; STRUCTURAL MODELS; SYMMETRY; X-RAY DIFFRACTION