For this purpose, a specific triribonucleoside (with a free 3′-terminal hydroxyl group) corresponding to the last three PUF repeats of the PUF protein serves as the starting primer, and dinucleoside pyrophosphate or mononucleoside 3′,5′-biphosphates serve as building blocks.
Specifically, if the building block is mononucleoside 3′,5′-biphosphate, ATP should be included for ligation; if it is dinucleoside pyrophosphate, ATP is not required.The third approach to assemble these mono- and diribonucleotides into oligoribonucleotides is to use condensation agents such as cyanogen bromide () and montmorillonite ().
The Building Blocks of DNA Replication are ..
OPPs and homologous proteins belong to a class of enzymes named prenyltransferases, which are a wide array of enzymes that are involved in the synthesis of linear isoprenyl pyrophosphates and that catalyze the condensation reaction of IPP with allylic substrates such as the C5 dimethylallyl pyrophosphate (DMAPP), the C15 FPP or the C20 geranylgeranyl pyrophosphate (GGPP) for chain elongation using the five-carbon IPP as a building block (Søballe & Poole, 1999; Liang et al., 2002). The products of varying chain length, such as steroids, carotenoids, quinones, dolichols, prenylated proteins and archaeal membrane lipids, are then utilized as precursors for many compounds involved in a variety of essential biological functions and signalling pathways (Sun et al., 2005). According to the stereochemical outcome of their products, prenyltransferases can be classified as cis- and trans-prenyltransferases (Kharel & Koyama, 2003; Ogura & Koyama, 1998). The cis-prenyltransferases are involved in catalyzing the synthesis of larger products from C55 to C120 from farnesyl pyrophosphate, while trans-prenyltransferases generally generate products shorter than C55 from farnesyl pyrophosphate (Asawatreratanakul et al., 2003; Sato et al., 1999). OPPs belongs to the latter.