Bovine rhodopsin is a photoreceptor protein that is an integral part of the disc

Question

Bovine rhodopsin is a photoreceptor protein that is an integral part of the disc membranes of retinal rod cells and plays a key role in vision. It has a tightly bound 11-c/s-retinal that has a strong absorbance at about 500 nm. As part of the vision cycle, the retinal is bleached by conversion to the trans-isomer. The protein has a molecular weight of 28,000 - 40,000. Three sites were labeled on the protein with fluorescent probes, sites A, B, and C. Fluorescence resonance energy transfer was measured between these three sites and the retinal and between the three sites themselves [C.-W. Wu and L. Stryer, Proc. Natl. Acad. Sci. USA 69, 1104 (1972)]. Some of the results are summarized in the following table. What is the molecular structure of 11-cis-retinal? Calculate the distances between these six sites. A protein of molecular weight 28,00 - 40,000 that is spherical has a radius of 40 - 45 A. What can you say about the shape of rhodopsin?

Explanation / Answer

a) The molecular structure of 11-cis-retinal is shown below

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.