生物化学简答全.pdfVIP

生物化学简答（王镜岩第三版加自己补充） 整理者：张守兵 2007.3.6 2006 年诺贝尔生理与医学奖得主是谁？介绍其研究成果及应用前景。 Andrew Fire and Craig Mello won the Nobel Prize in Medicine of 2006 for their discovery of RNA interference or RNAi. Andrew Fire 和 Craig Mello 因发现RNAi 机制而获得了 2006 年的诺贝尔医学奖。 Mechanism of RNA interference (RNAi) in mammalian systems ：哺乳动物中RNAi 机制 RNA interference is mediated by small interfering RNAs (siRNAs) which are intracellularly generated from long endogenous or exogenous double-stranded RNA molecules (dsRNAs) through the cleavage activity of a ribonuclease (核糖核酸酶) III-type protein. More specifically ， the protein Dicer which typically contains an N-terminal RNA helicase domain ， an RNA-binding so-called Piwi/Argonaute/Zwille (PAZ) domain ， two RNase III domains and a double-stranded RNA binding domain (dsRBD) ， leads to the formation of short 21–23 nt duplexes with a symmetric 2 nt overhang at the 3′-end and a 5′-phosphate and 3′-hydroxy group referred to as siRNAs. This siRNA molecule is incorporated into a nuclease-containing multi-protein complex called RNA-induced silencing complex (RISC) which becomes activated (RISC*) upon the loss of one strand of the siRNA duplex by an RNA helicase activity. By binding of the now single-stranded siRNA to a complementary target RNA molecule ， it sequence-specifically guides the RISC complex to the target RNA and induces endonucleolytic cleavage of the mRNA strand within the target site. Due to the generation of unprotected RNA ends， this cleavage leads to the rapid degradation of the entire mRNA molecule while the RISC complex is recovered for further cleavage cycles. 2006 年诺贝尔化学奖得主是谁？介绍其研究成果。 Roger Kornberg is being honored for his work in genetic research. The Nobel Prize committee said he showed how information in the nucleus of genes is copied and moved to other parts of a cell. The committee said he was the first to show pictures of t