Open AccessProtons and Mg 2+ Cations as Probes in Investigating the Role of GTP in Initiation Complex Formation
Author(s) -
BEAUDRY Patrice,
BEGARD Evelyne,
GRUNBERGMANAGO Marianne
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12784.x
Subject(s) - gtp' , chemistry , guanosine , guanosine triphosphate , polyelectrolyte , biophysics , hydrolysis , crystallography , biochemistry , enzyme , organic chemistry , biology , polymer
fMet‐tRNA fMet binding to both 30‐S subunits and to 70‐S particles is dependent on both pH and Mg 2+ concentration: for fMet‐tRNA fMet binding to 70‐S particles, variations of pH and Mg 2+ concentration are tightly interdependent. This behavior can be interpreted by the polyelectrolyte theory as a direct consequence of the fact that the binding occurs in a polyanionic microenvironment. The pH‐dependent binding to 70‐S particles clearly shows the involvement of two prototropic groups which appear to be those carrying out GTP hydrolysis, therefore directly linked to initiation complex formation; in the presence of a non‐hydrolyzable analogue to GTP, guanosine 5′‐[β,γ‐imido]triphosphate, the binding of fMet‐tRNA fMet shows much less interdependence between variation of pH and Mg 2+ concentration.