Folding and stability of mutant scaffolding proteins defective in P22 capsid assembly.


Bacteriophage P22 scaffolding subunits are elongated molecules that interact through their C termini with coat subunits to direct icosahedral capsid assembly. The soluble state of the subunit exhibits a partially folded intermediate during equilibrium unfolding experiments, whose C-terminal domain is unfolded (Greene, B., and King, J. (1999) J. Biol. Chem. 274, 16135-16140). Four mutant scaffolding proteins exhibiting temperature-sensitive defects in different stages of particle assembly were purified. The purified mutant proteins adopted a similar conformation to wild type, but all were destabilized with respect to wild type. Analysis of the thermal melting transitions showed that the mutants S242F and Y214W further destabilized the C-terminal domain, whereas substitutions near the N terminus either destabilized a different domain or affected interactions between domains. Two mutant proteins carried an additional cysteine residue, which formed disulfide cross-links but did not affect the denaturation transition. These mutants differed both from temperature-sensitive folding mutants found in other P22 structural proteins and from the thermolabile temperature-sensitive mutants described for T4 lysozyme. The results suggest that the defects in these mutants are due to destabilization of domains affecting the weak subunit-subunit interactions important in the assembly and function of the virus precursor shell. Study holds ProTherm entries: 6444, 6445, 6446, 6447, 6448, 6449 Extra Details: partially folded intermediate; temperature-sensitive;,cysteine; disulfide cross-link

Submission Details

ID: Fg3LEb3j3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:32 p.m.

Version: 1

Publication Details
Greene B;King J,J. Biol. Chem. (1999) Folding and stability of mutant scaffolding proteins defective in P22 capsid assembly. PMID:10347166
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Scaffolding protein P26748 VG08_BPP22