Critical Regions for Assembly of Vertebrate Nonmuscle Myosin II
详细信息 查看全文
- 作者：Takashi Nakasawa ; Masayuki Takahashi ; Fumiko Matsuzawa ; Seiichi Aikawa ; Yuki Togashi ; Takayuki Saitoh ; Akihiko Yamagishi ; and Michio Yazawa
- 刊名：Biochemistry
- 出版年：2005
- 出版时间：January 11, 2005
- 年：2005
- 卷：44
- 期：1
- 页码：174 - 183
- 全文大小：2427K
- 年卷期：v.44,no.1(January 11, 2005)
- ISSN：1520-4995
文摘
Myosin II molecules assemble and form filaments through their C-terminal rod region, andthe dynamic filament assembly-disassembly process of nonmuscle myosin II molecules is important forcellular activities. To estimate the critical region for filament formation of vertebrate nonmuscle myosinII, we assessed the solubility of a series of truncated recombinant rod fragments of nonmuscle myosinIIB at various concentrations of NaCl. A C-terminal 248-residue rod fragment (Asp 1729-Glu 1976)was shown by its solubility behavior to retain native assembly features, and two regions within it werefound to be necessary for assembly: 35 amino acid residues from Asp 1729 to Thr 1763 and 39 aminoacid residues from Ala 1875 to Ala 1913, the latter containing a sequence similar to the assemblycompetence domain (ACD) of skeletal muscle myosin. Fragments lacking either of the two regions weresoluble at any NaCl concentration. We referred to these two regions as nonmuscle myosin ACD1 (nACD1)and nACD2, respectively. In addition, we constructed an 
-helical coiled-coil model of the rod fragment,and found that a remarkable negative charge cluster (termed N1) and a positive charge cluster (termedP2) were present within nACD1 and nACD2, respectively, besides another positive charge cluster (termedP1) in the amino-terminal vicinity of nACD2. From these results, we propose two major electrostaticinteractions that are essential for filament formation of nonmuscle myosin II: the antiparallel interactionbetween P2 and N1 which is essential for the nucleation step and the parallel interaction between P1 andN1 which is important for the elongation step.
-helical coiled-coil model of the rod fragment,and found that a remarkable negative charge cluster (termed N1) and a positive charge cluster (termedP2) were present within nACD1 and nACD2, respectively, besides another positive charge cluster (termedP1) in the amino-terminal vicinity of nACD2. From these results, we propose two major electrostaticinteractions that are essential for filament formation of nonmuscle myosin II: the antiparallel interactionbetween P2 and N1 which is essential for the nucleation step and the parallel interaction between P1 andN1 which is important for the elongation step.