Rate-temperature relationships in lambda-repressor fragment lambda 6-85 folding.
Two classes of lambda(6-85) mutants (those richer in alanine, and those richer in glycine) have very similar slopes in an Arrhenius plot of the unfolding rates but very different temperature dependencies of the folding rates. Temperature-dependent interactions (e.g., hydrophobicity) play a large role in the initial stages of folding but not in the initial stages of unfolding of lambda(6-85). Placement of the transition state in terms of its surface exposure and entropy shows that at least two reaction coordinates are required to describe folding of all mutants over the full temperature range. The unusual Arrhenius plots of the very fastest mutant provide an additional kinetic signature for downhill folding.
Center for Biophysics and Computational Biology and Department of Chemistry, University of Illinois at Urbana-Champaign, Illinois 61801, USA.
Wei Yuan
WY
Yang
Martin
M
Gruebele
D000409:Alanine / Q000235:genetics; D010582:Bacteriophage lambda / Q000737:chemistry* / Q000235:genetics; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D005998:Glycine / Q000235:genetics; D057927:Hydrophobic and Hydrophilic Interactions; D008956:Models, Chemical; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics; D013696:Temperature; D013816:Thermodynamics; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D000409:Alanine; D005998:Glycine