PRIMARY STRUCTURE AND TOPOLOGY OF BETA 1-4 GALATOSYLTRANSFERASE

Beta 1-4 半乳糖基转移酶的一级结构和拓扑结构

• 批准号: 3916335
• 负责人: P K QASBA
• 金额: --
• 依托单位: DIVISION OF CANCER BIOLOGY AND DIAGNOSIS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3916335
• 关键词: complementary DNA; enzyme mechanism; enzyme structure; galactosyltransferases; messenger RNA; molecular cloning; nucleic acid hybridization; protein sequence; protein structure

Studies on the primary structure of beta 1-4 galactosyltransferase (1-4 galtransferase) continued in this year. To deduce the complete amino acid sequence of 1-4 galtransferase, genomic clones were isolated. NH2-terminal end sequence derived from the cDNA and genomic clones showed that the 1-4 galtransferase is synthesized as a larger precursor. The soluble and secreted form is missing approximately 72-residue-NHz-terminal peptide which contains the membrane anchoring domain as well as the potential protease susceptible sequence - Arg-x-x-Arg-Arg-Leu-. The milk enzyme can be generated from the larger precursor by proteolytic cleavage between the NHz-signal-anchor and the catalytic domain. The topology of the Golgi and cell surface 1-4 galtransferase can be predicted to be similar to a class of membrane proteins, like the transferrin receptor, the asialoglycoprotein receptor, the beta- galactoside alpha-2, 6-sialyltransferase, the influenza virus sialidase etc., which have an NH2-terminal "stem" structure extending from the luminal side of the transmembrane bilayer to the cytoplasmic side. The bulk of the protein structure, which carries the main function, faces the lumen side.

研究β1-4半乳糖基转移酶的主要结构 （1-4 Galtransferase）在今年继续进行。 推断 1-4个Galtransferase，基因组克隆的完整氨基酸序列 被隔离了。 源自cDNA和的NH2末端序列 基因组克隆表明合成1-4的Galtransferase酶是合成的 作为较大的前体。 可溶性和分泌的形式缺失 大约有72个残留的NHz末端肽，其中包含 膜锚定域以及潜在蛋白酶 易感序列-Arg-X-X-ARG-ARG-LEU-。 牛奶酶可以 通过蛋白水解裂解从较大的前体产生 在NHz信号锚定和催化域之间。 这 高尔基体和细胞表面的拓扑结构1-4 Galtransferass可以是 预计将类似于一类膜蛋白，例如 转铁蛋白受体，Asialogolototin受体，β- 半乳糖苷Alpha-2，6-溶酶体转移酶，流感病毒 唾液酸酶等，具有NH2末端的“茎”结构 从跨膜双层的腔侧延伸到 细胞质侧。 大部分蛋白质结构 主要功能面向管腔侧。