Separate GTP binding and GTPase activating domains of a Gα subunit
DW Markby, R Onrust, HR Bourne - Science, 1993 - science.org
DW Markby, R Onrust, HR Bourne
Science, 1993•science.orgMost members of the guanosine triphosphatase (GTPase) superfamily hydrolyze guanosine
triphosphate (GTP) quite slowly unless stimulated by a GTPase activating protein or GAP.
The α subunits (Gα) of the heterotrimeric G proteins hydrolyze GTP much more rapidly and
contain an∼ 120-residue insert not found in other GTPases. Interactions between a Gα
insert domain and a Gα GTP-binding core domain, both expressed as recombinant proteins,
show that the insert acts biochemically as a GAP. The results suggest a general mechanism …
triphosphate (GTP) quite slowly unless stimulated by a GTPase activating protein or GAP.
The α subunits (Gα) of the heterotrimeric G proteins hydrolyze GTP much more rapidly and
contain an∼ 120-residue insert not found in other GTPases. Interactions between a Gα
insert domain and a Gα GTP-binding core domain, both expressed as recombinant proteins,
show that the insert acts biochemically as a GAP. The results suggest a general mechanism …
Most members of the guanosine triphosphatase (GTPase) superfamily hydrolyze guanosine triphosphate (GTP) quite slowly unless stimulated by a GTPase activating protein or GAP. The α subunits (Gα) of the heterotrimeric G proteins hydrolyze GTP much more rapidly and contain an ∼120-residue insert not found in other GTPases. Interactions between a Gα insert domain and a Gα GTP-binding core domain, both expressed as recombinant proteins, show that the insert acts biochemically as a GAP. The results suggest a general mechanism for GAP-dependent hydrolysis of GTP by other GTPases.
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