Chemistry of the active site of rhodopsin

Akhtar, Muhammad; Hirtenstein, M. D.

doi:10.1042/bj1150607

Cited by 22 publications

(5 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently in a short communication, Akhtar and Hirtenstein (1969) presented results in agreement with those reported in our earlier note , which have been elaborated in this paper and the following one (Kimbel et al, 1970). The supporting evidence, which these authors present, verifies the role of phosphatidylethanolamine in the native chromophoric binding site as A-retinylidenephosphatidylethanolamine, as well as the subsequent transfer of the chromophore to the e-amino group of a lysyl unit in the backbone protein.…”

Section: Added In Proofsupporting

confidence: 90%

Determination of the chromophoric binding site in native bovine rhodopsin

Poincelot¹,

Millar²,

Kimbel³

et al. 1970

Biochemistry

View full text Add to dashboard Cite

Section: Added In Proofsupporting

confidence: 90%

Determination of the chromophoric binding site in native bovine rhodopsin

Poincelot¹,

Millar²,

Kimbel³

et al. 1970

Biochemistry

View full text Add to dashboard Cite

“…While the presence of such a retinal isomerase may still be an important factor in the pigment epithelium (Bliss, 1951), the unequivocal presence of a retinylidene Schiff base of PE (NRPE) in ROS (Anderson and Maude, 1970) and the unequivocal certainty that the photosensitive chromophore of rhtdopsin is a protonated Schiff base of retinal and lysine of opsin (Oseroff and Callendar, 1974) resolves the controversy over the role of NRPE (Poincelot et al, 1970a. b ;Daemen and Bonting, 1969; Akhtar and Hirtenstein, 1969) into the question of what role does NRPE play in the isomerization reaction.…”

Section: Introductionmentioning

confidence: 99%

A POSSIBLE MECHANISM FOR THE ROLE OF N‐RETINYLIDENE PHOSPHATIDYL ETHANOLAMINE IN THE REGENERATION OF RHODOPSIN

Rabinovitch

1979

Photochem & Photobiology

View full text Add to dashboard Cite

Abstract— A series of molecular orbital calculations on a model Schiff base comparable to protonated N‐retinylidene phosphatidyl ethanolamine isomers has been made. The effect of the charged oxygen atoms of the phosphate moiety on the distribution of positive charge along the polyene chain of these isomers has been calculated. The stabilizing coulombic energy of interaction of these opposite charges and the possibility of free rotation around carbonxarbon double bonds in the electronically excited state has led to the conclusion that an 11‐cis Schiff base isomer is the most probable product of the photoisomerization of an all‐trans Schiff base. The formation of a stable unprotonated all‐trans Schiff base in aqueous detergent dispersion and its subsequent conversion to the protonated form, both with absorption spectra in conformity with the literature, is demonstrated.

show abstract

“…The observations led these workers to suggest that the active site of native rhodopsin contains the retinyl moiety linked to the amino group of phosphatidylethanolamine and that the conversion of rhodopsin into metarhodopsin II may be attended by the migration of the chromophore from lipid to c-amino group of a lysyl residue in the backbone protein (Poincelot, Millar, Kimbel & Abrahamson, 1969, 1970. A qualified support for this view was provided by the work of Akhtar & Hirtenstein (1969) who demonstrated the isolation of some N-retinylphosphatidylethanolamine after the denaturation of native rhodopsin with trichloroacetic acid (Kito, Suzuki, Azuma & Sekoguti, 1968). We have in this paper examined a number of independently prepared samples of rhodopsin and our results now show that a phospholipid-linked retinyl derivative can be isolated only from certain types of preparations.…”

mentioning

confidence: 63%

“…These experiments led these workers to suggest that the active site of rhodopsin contains phosphatidylethanolamine linked to the polyene moiety. A qualified support for this view was provided by our previous work (Akhtar & Hirtenstein, 1969).…”

Section: Percentage Of Radioactivitymentioning

confidence: 90%

A convenient synthesis of labelled rhodopsin and studies on its active site

Hirtenstein

Akhtar

1970

Biochemical Journal

View full text Add to dashboard Cite

Digitonin solutions of labelled rhodopsin, containing (3)H in the retinyl moiety, were prepared by two related methods. Labelled rhodopsin was also prepared for the first time in cetyltrimethylammonium bromide and purified by column chromatography. It was shown that only certain rhodopsin preparations on denaturation in the dark and the reduction with sodium borohydride gave up to 60% of the radioactivity in a fraction characterized as N-retinylphosphatidylethanolamine. Such preparations also gave a lipid-linked retinyl moiety at the metarhodopsin-I stage, but, as expected, a protein-linked retinyl moiety at the metarhodopsin-II stage. Other preparations however, gave exclusively protein-bound radioactivity at the native-rhodopsin, metarhodopsin-I and metarhodopsin-II stages. It is therefore conceivable that the formation of N-retinylphosphatidylethanolamine is due to a non-enzymic reaction resulting from the transfer of the retinyl moiety from its native site to an amino group of a favourably oriented phospholipid molecule. The only firmly established aspect of the rhodopsin active site remains the demonstration in our previous work that at the metarhodopsin-II stage the retinyl moiety is linked to an in-amino group of lysine. On the basis of chemical reactivity it is argued that the light-induced conversion of rhodopsin into metarhodopsin II involves a profound conformational change resulting in the dislocation of the retinylideneiminium chromophore from a non-polar environment in rhodopsin to a polar environment in metarhodopsin II.

show abstract

Chemistry of the active site of rhodopsin

Cited by 22 publications

References 10 publications

Determination of the chromophoric binding site in native bovine rhodopsin

Determination of the chromophoric binding site in native bovine rhodopsin

A POSSIBLE MECHANISM FOR THE ROLE OF N‐RETINYLIDENE PHOSPHATIDYL ETHANOLAMINE IN THE REGENERATION OF RHODOPSIN

A convenient synthesis of labelled rhodopsin and studies on its active site

Contact Info

Product

Resources

About