Hargrave P A, Fong S L
J Supramol Struct. 1977;6(4):559-70. doi: 10.1002/jss.400060409.
The amino terminus of bovine rhodopsin is blocked and has the sequence x-Met-Asn(CHO)-Gly-Thr-Glu-Gly-Pro-Asn-Phe-Tyr-Val-Pro-Phe-Ser-Asn(CHO)-Lys-Thr-Gly-Val-Val-Arg, where CHO represents sites of carbohydrate attachment. The carboxyl-terminal sequence of rhodopsin is Val-Ser-Lys-Thr-Glu-Thr-Ser-Gln-Val-Ala-Pro-Ala. Upon short-term digestion of rod outer segment (ROS) membranes with thermolysin, opsin (similar to 35,000 daltons) is converted to a membrane-bound fragment O' (similar to 30,500 daltons) and 2 peptides containing 12 amino acids are released from the carboxyl terminus of rhodopsin into the supernatant. Upon long-term digestion of ROS with thermolysin, opsin and O' are replaced by the membrane-bound fragments F1 (similar to 25,000 daltons), and F2 (similar 9,500 daltons). When 32P-ROS are digested, F2 carries the 32P. Both O' and F1 contain the amino-terminal glycopeptide.
牛视紫红质的氨基末端被封闭，其序列为x-甲硫氨酸-天冬酰胺（CHO）-甘氨酸-苏氨酸-谷氨酸-甘氨酸-脯氨酸-天冬酰胺-苯丙氨酸-酪氨酸-缬氨酸-脯氨酸-苯丙氨酸-丝氨酸-天冬酰胺（CHO）-赖氨酸-苏氨酸-甘氨酸-缬氨酸-缬氨酸-精氨酸，其中CHO代表碳水化合物连接位点。视紫红质的羧基末端序列为缬氨酸-丝氨酸-赖氨酸-苏氨酸-谷氨酸-苏氨酸-丝氨酸-谷氨酰胺-缬氨酸-丙氨酸-脯氨酸-丙氨酸。用嗜热菌蛋白酶对杆状外段（ROS）膜进行短期消化后，视蛋白（约35,000道尔顿）转化为膜结合片段O′（约30,500道尔顿），并且从视紫红质的羧基末端释放出2个含12个氨基酸的肽进入上清液。用嗜热菌蛋白酶对ROS进行长期消化后，视蛋白和O′被膜结合片段F1（约25,000道尔顿）和F2（约9,500道尔顿）取代。当用32P标记的ROS进行消化时，F2带有32P。O′和F1都含有氨基末端糖肽。
