Probing the folding and unfolding of wild-type and mutant forms of bacteriorhodopsin in micellar solutions: Evaluation of reversible unfolding conditions

Guo Qiang Chen, Eric Gouaux

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

Wild-type and mutant forms of bacteriorhodopsin (sbR) from Halobacterium salinarium, produced by Escherichia coli overexpression of a synthetic gene, were reversibly unfolded in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 3-[(3-cholamidopropyl)dimethylamino]-2-hydroxyl-1-propane (CHAPSO), and sodium dodecyl sulfate (SDS) mixed micelles. To study the effect on protein stability by substitutions on the hydrophobic surface with polar residues, the unfolding behavior of a G113Q, G116Q mutant [sbR(Q2)] was compared to the wild-type sbR [sbR(WT)]. sbR(Q2) was more sensitive to SDS- induced unfolding than sbR(WT) under equilibrium conditions, and kinetic experiments showed that sbR(Q2) was more sensitive to acid-induced denaturation and thermal unfolding than sbR(WT). Since the mutations in sbR(Q2) were on the detergent-embedded hydrophobic surface of sbR, protein destabilization by these mutations supports the concept that the membrane- embedded segments are important for the stability of sbR. Our experiments provide the basis for studying he thermodynamic stability of sbR by evaluating reversible folding and unfolding conditions in DMPC/CHAPSO/SDS mixed micelles.

Original languageEnglish (US)
Pages (from-to)15380-15387
Number of pages8
JournalBiochemistry
Volume38
Issue number46
DOIs
StatePublished - Nov 16 1999
Externally publishedYes

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Bacteriorhodopsins
Sodium Dodecyl Sulfate
Phosphorylcholine
Micelles
Halobacterium
Synthetic Genes
Propane
Mutation
Denaturation
Protein Stability
Thermodynamics
Detergents
Hydroxyl Radical
Escherichia coli
Membrane Proteins
Thermodynamic stability
Substitution reactions
Hot Temperature
Genes
Experiments

ASJC Scopus subject areas

  • Biochemistry

Cite this

Probing the folding and unfolding of wild-type and mutant forms of bacteriorhodopsin in micellar solutions : Evaluation of reversible unfolding conditions. / Chen, Guo Qiang; Gouaux, Eric.

In: Biochemistry, Vol. 38, No. 46, 16.11.1999, p. 15380-15387.

Research output: Contribution to journalArticle

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