Neutron diffraction study on the location of the polyene chain of retinal in bacteriorhodopsin

Journal Article · Wed May 01 04:00:00 EDT 1985 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.82.10.3227· OSTI ID:5079823

Seiff, F; Wallat, I; Ermann, P; Heyn, M P

The authors report on the location of the chain part of the retinylidene chromophore in the projected density of bacteriorhodopsin as determined by neutron diffraction from the two-dimensional purple membrane lattice. For this purpose, partially deuterated retinal was synthesized containing 10 deuterons at positions C-8, C-10, C-12, C-14, C-19(3), and C-20(3) of the polyene chain. Two sets of dark-adapted samples were prepared in entirely different ways: (i) Deuterated retinal was incorporated biosynthetically during growth of the bacteria by using the mutant JW5, which is deficient in the synthesis of retinal. (ii) The chromophore was converted to retinal oxime, the resulting colorless apomembrane was regenerated with deuterated retinal, and the residual retinal oxime was removed by washing with bovine serum albumin. Characterization of these samples by x-ray diffraction, absorption, and flash spectroscopy showed that they were identical to native purple membrane samples as judged by these criteria. Fourier difference maps were calculated from the differences in inplane diffraction from the deuterated membranes and from protonated samples that were prepared in exactly the same way. At 8.7 A resolution, both maps show a single major peak at the same position with the center of mass of the labeled part of the chain (C-11) between helices 6 and 3 but closer to helix 6. It appears likely that the COOH-terminal helix G, to which retinal is attached at lysine-216, is either helix 2 or 6.

• OSTI ID: 5079823
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 10; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BARYONS
BODY
BODY AREAS
CAROTENOIDS
CELL CONSTITUENTS
CELL MEMBRANES
COHERENT SCATTERING
DEUTERIUM
DIFFRACTION
ELEMENTARY PARTICLES
EYES
FACE
FERMIONS
FOURIER ANALYSIS
HADRONS
HEAD
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEMBRANES
MOLECULAR STRUCTURE
NEUTRON DIFFRACTION
NEUTRONS
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PIGMENTS
POLYENES
PROTEINS
RETINA
RHODOPSIN
SCATTERING
SENSE ORGANS
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
TERPENES
X-RAY DIFFRACTION