What is the fine-grained topic of the following text: Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices [, , ].This entry represents the G protein-coupled receptor, rhodopsin-like family. Only return the topic.
G protein-coupled receptor, rhodopsin-like family