Tarkka T, Raatikainen E, Friman S, Oikarinen J
Department of Medical Biochemistry, University of Oulu, Finland.
Biochem Biophys Res Commun. 1995 Jul 17;212(2):509-14. doi: 10.1006/bbrc.1995.1999.
Chromatin has been proposed to share a common evolutionary origin and analogous mechanisms of action with various structures of cytoskeleton such as actin filaments. ATP has been shown to facilitate chromatin remodelling, but the exact site of its interaction with chromatin has not been elucidated. The facts, that ATP binds specifically to actin and promotes its polymerization, led us to characterize the possible domains involved in ATP binding in nucleosome. Comparison of the sequences of actin and the protein components of nucleosome suggests that H2A may contain an adenosine binding site similar to the adenosine motif of actin, H1 and/or H2B phosphate/Ca2+ binding sites corresponding to the phosphate 1 motif of actin, HMG17 a phosphate/Ca2+ binding site corresponding to the phosphate 2 motif of actin. The ability to bind ATP may be involved in the organization of chromatin into inactive solenoid-like structures in vivo.
有人提出染色质与细胞骨架的各种结构（如肌动蛋白丝）有着共同的进化起源和类似的作用机制。已证明ATP有助于染色质重塑，但其与染色质相互作用的确切位点尚未阐明。ATP能特异性结合肌动蛋白并促进其聚合，这一事实促使我们去鉴定核小体中可能参与ATP结合的结构域。肌动蛋白与核小体蛋白质成分的序列比较表明，H2A可能含有一个类似于肌动蛋白腺苷基序的腺苷结合位点，H1和/或H2B的磷酸/钙离子结合位点对应于肌动蛋白的磷酸1基序，HMG17的一个磷酸/钙离子结合位点对应于肌动蛋白的磷酸2基序。结合ATP的能力可能参与了体内染色质组织形成无活性的螺线管样结构。
