Folding behavior of a backbone-reversed protein: reversible polyproline type II to beta-sheet thermal transitions in retro-GroES multimers with GroES-like features.
IR@IMTECH: CSIR-Institute of Microbial Technology, Chandigarh
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| Title |
Folding behavior of a backbone-reversed protein: reversible polyproline type II to beta-sheet thermal transitions in retro-GroES multimers with GroES-like features.
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| Creator |
Ahmed, Shubbir
Shukla, Anshuman Guptasarma, Purnananda |
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| Subject |
QH301 Biology
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| Description |
The structural consequences of the reversal of polypeptide backbone direction (retro modification) remain insufficiently explored. Here, we describe the behavior of an engineered, backbone-reversed form of the 97 residues-long GroES co-chaperonin of Escherichia coli. FTIR and far-UV CD spectroscopy suggest that retro-GroES adopts a mixed polyproline type II (PPII)-beta-strand structure with a beta(II) type CD spectrum similar to that of GroES. Gel-filtration chromatography reveals that the protein adopts trimeric and/or pentameric quaternary structures, with solubility retained up to concentrations of 5.0-5.5 mg/ml in aqueous solutions. Mutations inserting a single tryptophan residue as a spectroscopic probe at three different sites cause no perturbation in the protein's CD spectral characteristics, or in its quaternary structural status. The protein is cooperatively dissociated, and non-cooperatively unfolded, by both guanidine hydrochloride and urea. Intriguingly, unlike with GroES, retro-GroES is not unfolded by heat. Instead, there is a reversible structural transition involving conversion of PPII structure to beta sheet structure, upon heating, with no attendant aggregation even at 90 degrees C. Retro-GroES does not bind GroEL. In summary, some structure-forming characteristics of GroES appear to be conserved through the backbone reversal process, although the differential conformational behavior upon heating also indicates differences.
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| Publisher |
Elsevier Science
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| Date |
2008-06
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://crdd.osdd.net/open/612/1/guptasarma08.11.pdf
Ahmed, Shubbir and Shukla, Anshuman and Guptasarma, Purnananda (2008) Folding behavior of a backbone-reversed protein: reversible polyproline type II to beta-sheet thermal transitions in retro-GroES multimers with GroES-like features. Biochimica et biophysica acta, 1784 (6). pp. 916-23. ISSN 0006-3002 |
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| Relation |
http://www.sciencedirect.com/science/article/pii/S1570963908000721
http://crdd.osdd.net/open/612/ |
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