Single-site mutations in a hyperthermophilic variant of the B1 domain of protein G result in self-assembled oligomers

Scott C. Meyer, Carmen Huerta, Indraneel Ghosh

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We have characterized two homologous, single-point core mutants of a 57-residue, hyperthermophilic variant of the B1 domain of protein G (HTB1). These single-point mutations in HTB1 replace a Phe residue in the hydrophobic core with either a Glu or Asp residue. Both of these homologous core-variant mutants undergo significant structural rearrangement from the native, monomeric fold and exist as stable soluble oligomeric species of 5 and 30 nm in diameter. Gel-filtration, dynamic light scattering, circular dichroism spectroscopy, fluorescence spectroscopy, along with Congo Red and Thioflavin T binding clearly demonstrated that these core-variants undergo significant structural rearrangement from the native, monomeric ubiquitin fold. The two oligomeric species did not equilibrate over extended periods of time and displayed distinct secondary structures. The larger of the two species was found to possess structural features that are reminiscent of an emerging class of protein assemblies prone to β-sheet-mediated aggregation. These results are significant as there are very few examples of extensive conformational or oligomerization switching brought about by single-point mutations in a stable protein-fold.

Original languageEnglish (US)
Pages (from-to)2360-2368
Number of pages9
JournalBiochemistry
Volume44
Issue number7
DOIs
StatePublished - Feb 22 2005

Fingerprint

Point Mutation
Oligomers
Congo Red
Mutation
Fluorescence Spectrometry
Viperidae
Circular Dichroism
Ubiquitin
Circular dichroism spectroscopy
Gel Chromatography
Spectrum Analysis
Oligomerization
Proteins
Fluorescence spectroscopy
Dynamic light scattering
Agglomeration
Gels
Protein Domains
thioflavin T
Dynamic Light Scattering

ASJC Scopus subject areas

  • Biochemistry

Cite this

Single-site mutations in a hyperthermophilic variant of the B1 domain of protein G result in self-assembled oligomers. / Meyer, Scott C.; Huerta, Carmen; Ghosh, Indraneel.

In: Biochemistry, Vol. 44, No. 7, 22.02.2005, p. 2360-2368.

Research output: Contribution to journalArticle

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