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Juxtamembrane tryptophans have distinct roles in defining the OmpX barrel–micelle boundary and facilitating protein–micelle association
Author(s) -
Chaturvedi Deepti,
Mahalakshmi Radhakrishnan
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.10.017
Subject(s) - micelle , folding (dsp implementation) , chemistry , barrel (horology) , protein folding , biophysics , bacterial outer membrane , amphiphile , crystallography , biochemistry , materials science , biology , organic chemistry , aqueous solution , escherichia coli , gene , electrical engineering , copolymer , composite material , engineering , polymer
Defining the span of the transmembrane region, a key requirement to ensure correct folding, stability and function of bacterial outer membrane β‐barrels, is assisted by the amphipathic property of tryptophan. We demonstrate the unique and distinctive properties of the interface Trp76 and Trp140 of outer membrane protein X, and map their positional relevance to the refolding process, barrel formation and the resulting stability in dodecylphosphocholine micelles. The solvent‐exposed Trp76 displays a rigid interfacial localization, whereas Trp140 is relatively micelle‐solvated and contributes to barrel folding and global OmpX stability. Kinetic contribution to OmpX stability is influenced by the two tryptophans. Differential associations of the indoles with the detergent milieu therefore contribute to micelle‐assisted β‐barrel folding and concomitant OmpX stability.