人間의 c-Ha-ras發癌性 蛋白質에 結合되어 있는 GDP와 GTP의 形態 比較 = The differences in conformation between GTP and GDP as bound to human c-Ha-ras proteins

다국어 초록 (Multilingual Abstract)

A truncated human c-Ha-ras gene product 〔ras(1-17)protein〕in which glutamine-61 was replaced by leucine 〔ras(L61/1-171)protein〕, was prepared and ligand was exchanged from GDP to GTPγS 〔Guanosine 5'(3-0-thio) triphosphate〕.
A mass production of ras protein bound with GTPγS was possible using ultra-filtration with chealating agent. GTPγS bound to c-Ha-ras protein was clearly confirmed by ultra-violet spectroscopy and phosphorus nuclear magnetic resonance.
The conformations of a bound GDP and a bound GTP to a ras(L61/1-171)protein were compared by time dependent nuclear Overhauser effect (NOE) spectroscopy.
The dependences of the H1' and H8 proton resonance intensities on duration of time-dependent NOE profiles, and the conformation of the protein-bound GDP and GTPγS were elu??dated ; as for the bound GDP, the guanosine moiety takes the antiform about N-glycosidic bond with the dihedral angle of χ=-124±2° and the riose ring takes the C2'-endo form(Ha. 1990).
Whereas the bound GTPγS, the guanosine moiety, takes the anti form about N-glycosidic bond with the dihedral angle of χ=-80±2°and the ribose ring takes the C3'-endo form
The conformations around effector region are of the regular structure in the GDP-bound state, and largely distorted in the GTPγS-bound state, whichis probably related to the conformational activation of the effector region of ras proteins by ligand substitution of GDP with GTPγS.
The role of the interaction between the bound guanine nucleotide and effector region is discussed with regard to the mechanism of the ras protein functions.

목차 (Table of Contents)

• Ⅰ. 서 론
• Ⅱ. 실험재료 및 방법
• Ⅲ. 결과 및 고찰
• References
• Summary