Structural and biochemical identity of retinal rod outer segment membrane guanylate cyclase.
Structural and biochemical identity of retinal rod outer segment membrane guanylate cyclase.
复制标题
视网膜杆外节膜鸟苷酸环化酶的结构和生化特性。
DOI：
10.1006/bbrc.1993.1900
复制
发表时间：
1993
影响因子：
3.1
通讯作者：
Sitaramayya,A
中科院分区：
文献类型：
--
作者：
Margulis,A;Goraczniak,RM;Duda,T;Sharma,RK;Sitaramayya,A
最近的分子克隆报道表明，脊椎动物视网膜中至少存在三种膜鸟苷酸环化酶：（1）心房利钠因子受体鸟苷酸环化酶（ANF-RGC），（2）C型利钠肽受体鸟苷酸环化酶（CNP-RGC），和（3）“视网膜鸟苷酸环化酶”（RetGC）。前两种环化酶的具体细胞定位尚不清楚，但RetGC明显定位于感光细胞，表明它参与视觉转导。与确定的鸟苷酸环化酶，是连接到光转导的总体目标，我们比较了生化特征的112 kDa的牛杆外段膜鸟苷酸环化酶（ROS-GC）与RetGC，ANF-RGC和CNP-RGC的结构和调节特性。纯化的ROS-GC的N-末端和两个内部肽序列与RetGC的相应序列的相似性约为90%，与利钠肽受体环化酶的序列相似性约为30%。ROS-GC的胰蛋白酶肽段有一段19个氨基酸的序列，在其他三种环化酶中没有相应的序列。ROS-GC被ATP抑制，但ANF-RGC和CNP-RGC在各自的肽激素存在下被ATP激活。这些结果表明，ROS-GC代表了膜鸟苷酸环化酶家族的一个新亚型，其在结构和生物化学上与其他视网膜环化酶不同。
Recent molecular cloning reports show that there are at least three membrane guanylate cyclases in vertebrate retina: (1) atrial natriuretic factor receptor guanylate cyclase (ANF-RGC), (2) C-type natriuretic peptide receptor guanylate cyclase (CNP-RGC), and (3) "retinal guanylate cyclase" (RetGC). The specific cellular localization of the first two cyclases is unknown, but RetGC is apparently localized in photoreceptor cells, suggesting that it participates in visual transduction. With the overall objective of identifying the guanylate cyclase that is linked to phototransduction, we compared the structural and regulatory properties of the biochemically characterized 112 kDa bovine rod outer segment membrane guanylate cyclase (ROS-GC) with those of RetGC, ANF-RGC and CNP-RGC. The N-terminal and two internal peptide sequences of purified ROS-GC had about 90% similarity with the corresponding sequences of the RetGC; the sequence identity with natriuretic peptide receptor cyclases was about 30%. A 19 amino acid long sequence from a tryptic peptide of ROS-GC had no corresponding sequence in the other three cyclases. ROS-GC was inhibited by ATP but ANF-RGC and CNP-RGC were activated by ATP in the presence of the respective peptide hormones. These results suggest that ROS-GC represents a new subtype of the membrane guanylate cyclase family that is structurally and biochemically distinct from the other retinal cyclases.