Thammana P, Cantor C R
Nucleic Acids Res. 1978 Mar;5(3):805-23. doi: 10.1093/nar/5.3.805.
Antibodies raised against N6, N6-dimethyl adenosine were used to study the environment and role of the m62Am62A sequences in the E. coli ribosome. It is observed that this sequence is exposed on the surface of isolated 30S subunits, but becomes inaccessible for IgG interaction upon heat activation. The m62Am62A sequence is also inaccessible for IgG interaction in 70S ribosomes or 30S subunits immediately after dissociation of 70S particles. The presence of IgGs results in a significant inhibition of IF3 binding to unactivated 30S particles. IF3 binding to activated 30S subunits is unaffected by the IgGs. Crosslinking of 30S proteins S18 and S21 with the bifunctional phenylene dimaleimide reagents results in a reduction in the extent of 30S-IgG interaction. From what is already known about the location of S18, S21 and the IF3 binding site, it is suggested that the m62Am62A sequence is located close to the initiator tRNA binding site of the 30S subunit during initiation of protein synthesis.
用针对N6,N6 - 二甲基腺苷产生的抗体来研究大肠杆菌核糖体中m62Am62A序列的环境和作用。观察到该序列在分离的30S亚基表面暴露,但在热激活后无法与IgG相互作用。在70S核糖体解离后立即得到的70S核糖体或30S亚基中,m62Am62A序列也无法与IgG相互作用。IgG的存在会显著抑制IF3与未激活的30S颗粒的结合。IF3与激活的30S亚基的结合不受IgG的影响。30S蛋白S18和S21与双功能亚苯基二马来酰亚胺试剂的交联导致30S - IgG相互作用程度降低。根据已知的S18、S21的位置以及IF3结合位点,推测在蛋白质合成起始过程中,m62Am62A序列位于30S亚基的起始tRNA结合位点附近。