GENE 500 Lecture Notes - Lecture 10: Guanine Nucleotide Exchange Factor, Gtpase, Intrinsic Activity
Document Summary
Large family of gtp binding and hydrolyzing proteins where a protein conformational change is caused by gtp binding: gap protei(cid:374)s (cid:272)o(cid:374)trol ho(cid:449) lo(cid:374)g g protei(cid:374) re(cid:373)ai(cid:374)s (cid:862)o(cid:374)(cid:863, gef proteins control ho(cid:449) (cid:862)off(cid:863) (cid:448)ersio(cid:374) gets tur(cid:374)ed (cid:862)o(cid:374)(cid:863) Gtpases are enzymes that bind to gtp and hydrolyze it to gdp. Gtpase protei(cid:374) adopts its a(cid:272)ti(cid:448)e, or (cid:862)o(cid:374),(cid:863) (cid:272)o(cid:374)for(cid:373)atio(cid:374) a(cid:374)d (cid:272)a(cid:374) i(cid:374)tera(cid:272)t (cid:449)ith target protei(cid:374)s to regulate their activities. When the bound gtp is hydrolyzed to gdp by the intrinsic gtpase a(cid:272)ti(cid:448)it(cid:455) of the protei(cid:374), the gtpase (cid:449)ith gdp (cid:271)ou(cid:374)d assu(cid:373)es a(cid:374) i(cid:374)a(cid:272)ti(cid:448)e, or (cid:862)off,(cid:863) (cid:272)o(cid:374)for(cid:373)atio(cid:374: gtpase-activating proteins, or gaps, can influence the rates of gtp hydrolysis. The binding of the active form of the gtpase to its targets is a form of noncovalent regulation. The gtpase switch can be turned back on when another protein, called a. Gef (guanine nucleotide exchange factor), mediates the replacement (exchange) of the bound gdp with a gtp molecule from the surrounding fluid.
