Format

Send to

Choose Destination
Biophys J. 2012 Sep 5;103(5):1011-9.

Contrasting factors on the kinetic path to protein complex formation diminish the effects of crowding agents.

Author information

1
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.

Abstract

The crowded environment of cells poses a challenge for rapid protein-protein association. Yet, it has been established that the rates of association are similar in crowded and in dilute solutions. Here we probe the pathway leading to fast association between TEM1 β-lactamase and its inhibitor protein BLIP in crowded solutions. We show that the affinity of the encounter complex, the rate of final complex formation, and the structure of the transition state are similar in crowded solutions and in buffer. The experimental results were reproduced by calculations based on the transient-complex theory for protein association. Both experiments and calculations suggest that while crowding agents decrease the diffusion constant of the associating proteins, they also induce an effective excluded-volume attraction between them. The combination of the two opposing effects thus results in nearly identical overall association rates in diluted and crowded solutions.

PMID:
23009850
PMCID:
PMC3433600
DOI:
10.1016/j.bpj.2012.08.009
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center