Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
FEBS Lett. 1998 Apr 3;425(3):460-4.

Moderate discrimination of REP-1 between Rab7 x GDP and Rab7 x GTP arises from a difference of an order of magnitude in dissociation rates.

Author information

  • 1Max-Planck Institute for Molecular Physiology, Department of Physical Biochemistry, Dortmund, Germany.

Abstract

The kinetics of the interaction of Rab7 with REP-1 have been investigated using the fluorescence of GDP and GTP analogs at the active site of Rab7. The results show that REP-1 has higher affinity for the GDP bound form of Rab7 (Kd=1 nM) than for the GTP bound form (Kd=20 nM). Both affinities should still be sufficient for the formation of stable complexes in the cell. The association reaction proceeds in two steps for the GDP bound form. The initial step is fast (k+1 = ca. 10[7] M[-1] s[-1]) and concentration dependent while the second represents a slow equilibration (k+2 + k-2 = 3.5 s[-1]) which has little effect on the overall equilibrium. The difference in affinity of the two nucleotide bound forms arises from a difference in dissociation rates (0.012 s[-1] for Rab7 x GDP and 0.2 s[-1] for Rab7 x GTP).

PMID:
9563513
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk