HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Galisteo, M. L. Articles by King, J. Search for Related Content PubMed PubMed Citation Articles by Galisteo, M. L. Articles by King, J. Social Bookmarking                      What's this?

Volume 270, Number 28, Issue of July 14, pp. 16595-16601, 1995
©1995 by The American Society for Biochemistry and Molecular Biology, Inc.

---

Mara L. Galisteo , Carl L. Gordon , Jonathan King

Temperature-sensitive folding (tsf) mutants of the phage P22 coat protein prevent newly synthesized polypeptide chains from reaching the conformation competent for capsid assembly in cells, and can be rescued by the GroEL chaperone (Gordon, C., Sather, S., Casjens, S., and King, J.(1994) J. Biol. Chem. 269, 27941-27951). Here we investigate the stabilities of wild-type and four tsf mutant unpolymerized subunits. Wild-type coat protein subunits denatured at 40 °C, with a calorimetric enthalpy of approximately 600 kJ/mol. Comparison with coat protein denaturation within the shell lattice (T = 87 °C, H 1700 kJ/mol) (Galisteo, M. L., and King, J.(1993) Biophys. J. 65, 227-235) indicates that protein-protein interactions within the capsid provide enormous stabilization. The melting temperatures of the subunits carrying tsf substitutions were similar to wild-type. At low temperatures, the tsf mutants, but not the wild-type, formed non-covalent dimers, which were dissociated at temperatures above 30 °C. Spectroscopic and calorimetric studies indicated that the mutant proteins have reduced amounts of ordered structure at low temperature, as compared to the wild-type protein. Although complex, the in vitro phenotypes are consistent with the in vivo finding that the mutants are defective in folding, rather than subunit stability. These results suggest a role for incompletely folded subunits as precursors in viral capsid assembly, providing a mechanism of reaching multiple conformations in the polymerized form.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				S. M. Doyle, E. Anderson, K. N. Parent, and C. M. Teschke A Concerted Mechanism for the Suppression of a Folding Defect through Interactions with Chaperones J. Biol. Chem., April 23, 2004; 279(17): 17473 - 17482. [Abstract] [Full Text] [PDF]

				L. A. Aramli and C. M. Teschke Single Amino Acid Substitutions Globally Suppress the Folding Defects of Temperature-sensitive Folding Mutants of Phage P22 Coat Protein J. Biol. Chem., August 6, 1999; 274(32): 22217 - 22224. [Abstract] [Full Text] [PDF]

				B. Greene and J. King Folding and Stability of Mutant Scaffolding Proteins Defective in P22 Capsid Assembly J. Biol. Chem., June 4, 1999; 274(23): 16141 - 16146. [Abstract] [Full Text] [PDF]

				W. S. Nakonechny and C. M. Teschke GroEL and GroES Control of Substrate Flux in the in Vivo Folding Pathway of Phage P22 Coat Protein J. Biol. Chem., October 16, 1998; 273(42): 27236 - 27244. [Abstract] [Full Text] [PDF]

				L. A. Aramli and C. M. Teschke Alleviation of a Defect in Protein Folding by Increasing the Rate of Subunit Assembly J. Biol. Chem., June 29, 2001; 276(27): 25372 - 25377. [Abstract] [Full Text] [PDF]