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Early stages of protein crystallization as revealed by emerging optical waveguide technology
Author(s) -
Boudjemline Attia,
Clarke David T.,
Freeman Neville J.,
Nicholson James M.,
Jones Gareth R.
Publication year - 2008
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889808005098
Subject(s) - crystallization , protein crystallization , waveguide , supersaturation , materials science , nucleation , interferometry , optics , chemistry , optoelectronics , physics , organic chemistry
A highly sensitive method for studying the onset of protein crystallization in real time using an optical‐waveguide‐based technique is reported. Dual polarization interferometry uses light from sensing and reference waveguides to produce an interference pattern, which when the sensing waveguide is immersed in a protein solution supplies information on the thickness and density of any protein adlayer on the sensing waveguide's surface. This technique provides evidence that crystallization proceeds via large protein aggregates but, more strikingly, shows dramatic light loss from the sensing waveguide at a very early stage during crystallization. The technique proves relatively insensitive to the crystallization of small molecules or poorly formed protein crystals and affords a method of distinguishing crystal formation from the formation of other protein aggregates or salt crystals. The experimental setup currently necessitates crystallization using the batch method, and precipitant mixing at high supersaturation is known to introduce a greater variability compared with methods such as vapour diffusion or dialysis, but first results promise to bridge the paucity of real‐time methods available to distinguish the onset of protein crystallization from other forms of aggregation.