Localization of N-terminal sequences in human AMP deaminase isoforms that influence contractile protein binding.
Localization of N-terminal sequences in human AMP deaminase isoforms that influence contractile protein binding.
复制标题
影响收缩蛋白结合的人 AMP 脱氨酶亚型中 N 端序列的定位。
DOI：
10.1006/bbrc.2001.5180
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Sabina,RL
中科院分区：
文献类型：
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作者：
Mahnke-Zizelman,DK;Sabina,RL
AMP 脱氨酶（AMPD，EC 3.5.4.6）与收缩装置元件的可逆关联是哺乳动物骨骼肌中酶调节的已确定机制。人类 AMPD 多基因家族的所有三个成员均含有具有不同 N 端和保守 C 端结构域的多肽的编码信息。在本研究中，构建了多达 111 个 (AMPD1)、214 个 (AMPD2) 和 126 个 (AMPD3) 残基的连续 N 端缺失突变体，且催化功能或蛋白质溶解度没有显着改变。整套活性酶用于扩展我们对 AMPD 收缩蛋白结合的理解。对大多数截短的活性酶的分析表明，所有三种亚型都可以与骨骼肌肌动球蛋白结合，并表明主要结合域位于每个多肽的 C 端 635-640 个残基内。然而，N 端序列的离散片段改变了这种行为。 AMPD1 多肽中的残基 54-83 有助于两种亚型 M 剪接体的高肌动球蛋白结合能力，尽管外显子 2− 酶与其外显子 2+ 对应物相比表现出显着更大的关联。相反，AMPD2 多肽中的残基 129-183 减少同种型 L 的肌动球蛋白结合。此外，AMPD3 多肽中的残基 1-48 显着抑制同种型 E 的收缩蛋白结合，从而允许该酶参与其他细胞内相互作用。
The reversible association of AMP deaminase (AMPD, EC 3.5.4.6) with elements of the contractile apparatus is an identified mechanism of enzyme regulation in mammalian skeletal muscle. All three members of the human AMPD multigene family contain coding information for polypeptides with divergent N-terminal and conserved C-terminal domains. In this study, serial N-terminal deletion mutants of up to 111 (AMPD1), 214 (AMPD2), and 126 (AMPD3) residues have been constructed without significant alteration of catalytic function or protein solubility. The entire sets of active enzymes are used to extend our understanding of the contractile protein binding of AMPD. Analysis of the most truncated active enzymes demonstrates that all three isoforms can associate with skeletal muscle actomyosin and suggests that a primary binding domain is located within the C-terminal 635–640 residues of each polypeptide. However, discrete stretches of N-terminal sequence alter this behavior. Residues 54–83 in the AMPD1 polypeptide contribute to a high actomyosin binding capacity of both isoform M spliceoforms, although the exon 2− enzyme exhibits significantly greater association compared to its exon 2+ counterpart. Conversely, residues 129–183 in the AMPD2 polypeptide reduce actomyosin binding of isoform L. In addition, residues 1–48 in the AMPD3 polypeptide dramatically suppress contractile protein binding of isoform E, thus allowing this enzyme to participate in other intracellular interactions.