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

Alexandrov K., Simon I., Iakovenko A., Holz B., Goody R.S. and Scheidig A.J. (1998) Moderate discrimination of REP-1 between Rab7·GDP and Rab7·GTP arises from a difference of an order of magnitude in dissociation rates. FEBS Letters, 425 3: 460-464. doi:10.1016/S0014-5793(98)00290-7


Author Alexandrov K.
Simon I.
Iakovenko A.
Holz B.
Goody R.S.
Scheidig A.J.
Title Moderate discrimination of REP-1 between Rab7·GDP and Rab7·GTP arises from a difference of an order of magnitude in dissociation rates
Journal name FEBS Letters   Check publisher's open access policy
ISSN 0014-5793
Publication date 1998-04-03
Year available 1998
Sub-type Article (original research)
DOI 10.1016/S0014-5793(98)00290-7
Open Access Status Not yet assessed
Volume 425
Issue 3
Start page 460
End page 464
Total pages 5
Place of publication AMSTERDAM
Publisher Wiley-Blackwell
Language eng
Subject 1303 Specialist Studies in Education
1304 Biophysics
1312 Molecular Biology
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-I has higher affinity for the GDP bound form of Rab7 (K-d = 1 nM) than for the GTP bound form (K-d = 20 nM). Both affinities should still be sufficient for the formation of stable completes 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 GDP and 0.2 s(-1) for Rab7.GTP). (C) 1998 Federation of European Biochemical Societies.
Keyword Fluorescence spectroscopy
Kinetics
Rab7
REP-1
Small GTP binding protein
Vesicular transpor
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: ResearcherID Downloads - Archived
 
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