GDP and GTP
نویسندگان
چکیده
The primary structures of interferon (IFN)-induced guanylate-binding proteins (GBPs) were deduced from cloned human and murine cDNAs. These proteins contained only two of the three sequence motifs typically found in GTP/GDP-binding proteins. The N(T)KXD motif, which is believed to confer guanine specificity in other nucleotide-binding proteins, was absent. Nevertheless, the IFN-induced GBPs exhibited a high degree of selectivity for binding to agarose-immobiized guanine nucleotides. An interesting feature of IFN-induced GBPs is that they strongly bound to GMP agarose in addition to GDP and GTP agaroses but failed to bind to ATP agarose and all other nucleotide agaroses tested. Both GTP and GMP, but not ATP, competed for binding of murine GBP-1 to agarose-immobilized GMP. The IFN-induced GBPs thus define a distinct novel family of proteins with GTP-binding activity. We further demonstrate that human and murine cells contain at least two
منابع مشابه
The Structural Basis of Oncogenic Mutations G12, G13 and Q61 in Small GTPase K-Ras4B
Ras mediates cell proliferation, survival and differentiation. Mutations in K-Ras4B are predominant at residues G12, G13 and Q61. Even though all impair GAP-assisted GTP → GDP hydrolysis, the mutation frequencies of K-Ras4B in human cancers vary. Here we aim to figure out their mechanisms and differential oncogenicity. In total, we performed 6.4 μs molecular dynamics simulations on the wild-typ...
متن کاملDetermination of absolute amounts of GDP and GTP bound to Ras in mammalian cells: comparison of parental and Ras-overproducing NIH 3T3 fibroblasts.
We devised enzyme-based methods to measure fmol amounts of GDP and GTP and applied these methods to measure absolute amounts of Ras-bound GDP and GTP in NIH 3T3 fibroblasts. We found that parental NIH 3T3 cells contained 509 and 1.3 fmol of Ras-bound GDP and GTP, respectively, per mg of cellular protein and that stable transfectants of NIH 3T3 cells overexpressing wild-type Ha-Ras contained 700...
متن کاملGDP-tubulin incorporation into growing microtubules modulates polymer stability.
Microtubule growth proceeds through the endwise addition of nucleotide-bound tubulin dimers. The microtubule wall is composed of GDP-tubulin subunits, which are thought to come exclusively from the incorporation of GTP-tubulin complexes at microtubule ends followed by GTP hydrolysis within the polymer. The possibility of a direct GDP-tubulin incorporation into growing polymers is regarded as ha...
متن کاملThermodynamics of the GTP-GDP-operated conformational switch of selenocysteine-specific translation factor SelB.
SelB is a specialized translation factor that binds GTP and GDP and delivers selenocysteyl-tRNA (Sec-tRNA(Sec)) to the ribosome. By analogy to elongation factor Tu (EF-Tu), SelB is expected to control the delivery and release of Sec-tRNA(Sec) to the ribosome by the structural switch between GTP- and GDP-bound conformations. However, crystal structures of SelB suggested a similar domain arrangem...
متن کاملDirected elongation model for microtubule GTP hydrolysis.
We propose a role for GTP hydrolysis in microtubule assembly in which the GTPase reaction serves to stabilize tubulin subunits in the microtubule. The GTPase reaction in tubulin subunits containing GTP at microtubule ends is presumed to occur predominately in subunits at one of the interfaces between a cap of GTP-containing tubulin subunit and a core of GDP-containing tubulin subunit in the mic...
متن کاملMechanism of glucagon stimulation of adenylate cyclase in the presence of GDP in rat liver plasma membranes.
In the present study on the specific role of GDP in regulation of the hepatic glucagon-sensitive adenylate cyclase system, two approaches were employed to eliminate the influence of the conversion of GDP during incubation: One was a time study during only the initial period of incubation with ATP as substrate and the other was a study using adenyl-5’-yl imidodiphosphate, a nonphosphorylating an...
متن کامل