Reversible inhibition of the proton pump bacteriorhodopsin by modification of tyrosine 64.

Lemke, Horst‐Dieter; Bergmeyer, J.; Straub, J.; Oesterhelt, Dieter

doi:10.1016/s0021-9258(18)34081-x

Cited by 29 publications

(9 citation statements)

References 20 publications

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“…This conclusion is based partly on the apparent of photocycle kinetic components and partly on transient UV-absorption changes indicating tyrosine deprotonation (Hess & Kuschmitz, 1979;Kalisky et al, 1981;Rosenbach et al, 1982;Fukumoto et al, 1984;Hanamoto et al, 1984;Bogomolni et al, 1978; Rafferty, 1979; Bogomolni, 1980; Kuschmitz & Hess, 1982). It has led several groups to investigate the effects of tyrosine modifications on these parameters (Konishi & Packer, 1978;Campos-Cavieres et al, 1979;Scherrer et al, 1981;Lam et al, 1983;Lemke & Oesterhelt, 1981;Rosenbach et al, 1982;Lemke et al, 1982). Combining observations of others with their own data, Kalisky et al have postulated that deprotonation of a tyrosine residue is a prerequisite for deprotonation of the Schiff base in the L -*• M transition (Kalisky et al, 1981).…”

Section: Discussionmentioning

confidence: 99%

“…The molecular mechanism of the light-driven proton translocation is not known. It apparently involves transient deprotonation of the Schiff-base linkage, of tyrosine(s) (Bogomolni et al, 1978;Hess & Kuschmitz, 1979;Scherrer et al, 1981;Lemke et al, 1982;Hanamoto et al, 1984), and of carboxyl groups (Rothschild et al, 1981;Engelhard et al, 1985). Selective chemical modification of specific amino acids provides information on their function and the arrangement of the polypeptide chain.…”

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confidence: 99%

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Effects of tyrosine-26 and tyrosine-64 nitration on the photoreactions of bacteriorhodopsin

Scherrer¹,

Stoeckenius²

1985

Biochemistry

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In the dark, all titratable tyrosine residues of bacteriorhodopsin have pK's of greater than 11.0, which may be caused by the hydrophobic environment for buried residues and by high negative charge density for surface residues [Scherrer, P., & Stoeckenius, W. (1984) Biochemistry 23, 6195-6202]. Under illumination, deprotonation of only one tyrosine is observed in the micro- and millisecond time ranges of the photocycle; this is Tyr-64. Nitration of Tyr-64 decreases the chromophore absorbance, shifts the absorption maximum to 535 nm, and affects photocycle kinetics. However, restoring its native pK by reduction after nitration has no effect on the changes in photocycle kinetics or absorbance of the chromophore. Nitration of Tyr-64 apparently causes a conformational change in bR, which is independent of the pK of its phenolic group. These observations contradict earlier conclusions that in the photocycle a tyrosine residue directly interacts with the Schiff base during its deprotonation or reprotonation. The protonation state of Tyr-26 and the alkaline chromophore transition are correlated, as shown earlier (Scherrer & Stoeckenius, 1984). Lowering the pK of Tyr-26 by nitration decreases the M-decay rate, and this effect is partially reversed by reduction of the nitro group. We conclude that Tyr-26 may be located close to the chromophore and interact with it; but its protonation state does not change at physiological pH and in the microsecond time range of the photocycle. Tyr-64 is apparently located at or close to the external surface; its modification strongly affects the chromophore but apparently indirectly and not through its protonation changes.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Effects of tyrosine-26 and tyrosine-64 nitration on the photoreactions of bacteriorhodopsin

Scherrer¹,

Stoeckenius²

1985

Biochemistry

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“…The benzoazotyrosines in the enzyme could not be reduced to 3-aminotyrosines with dithionite or borohydride as no loss of absorbance at 325 nm was found upon the addition of either of these reagents. Although reduction is expected to take place, its failure has been reported as well (Lemke et al, 1982). When p-hydroxybenzoate hydroxylase was inactivated by p-diazobenzoate, the diassociation constant of the modified enzyme-NADPH complex was 0.14 mM at pH 7 and I = 20 mM.…”

Section: Resultsmentioning

confidence: 99%

Chemical modification of tyrosine residues in p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens: assignment in sequence and catalytic involvement

Wijnands¹,

Weijer²,

Müller³

et al. 1986

Biochemistry

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p-Hydroxybenzoate hydroxylase was modified by diethyl pyrocarbonate at pH values greater than 7 and by p-diazobenzoate. Modification of the enzyme by diethyl pyrocarbonate abolishes the affinity of the enzyme for the substrate p-hydroxybenzoate. Modification by p-diazobenzoate has the same effect on the enzyme. The enzyme is protected against these modifications by the effector p-fluorobenzoate. The data indicate that the modification of one tyrosine residue in the active center of the enzyme is responsible for the loss of enzyme activity. This tyrosine residue has been identified by sequence studies using radioactively labeled p-diazobenzoate and was found to be most probably Tyr-222. Diethyl pyrocarbonate reacts with a tyrosine residue in the active center other than Tyr-222; the former could not be identified. Sequence studies further showed that Cys-211 is also partially modified by p-diazobenzoate. In addition, the sequence of residues 343-345 was found to be Ser-Trp-Trp instead of the tentative assignment Ser-Tyr-Trp made earlier. The results are briefly discussed on the basis of the existing three-dimensional model of the enzyme.

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“…A tyrosine deprotonation was reported to occur in concomitance with the formation of M (Hess & Kuschmitz, 1979;Hanamoto et al, 1984). Specific chemical modifications of Tyr-64 and Tyr-26 in BR have also been exploited to clarify the role of tyrosines (Lemke & Oesterhelt, 1981;Lemke et al, 1982;Rosenbach et al, 1982;Scherrer & Stoeckenius, 1984.…”

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confidence: 99%

Deprotonation of tyrosines in bacteriorhodopsin as studied by Fourier transform infrared spectroscopy with deuterium and nitrate labeling

et al. 1987

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Reversible inhibition of the proton pump bacteriorhodopsin by modification of tyrosine 64.

Cited by 29 publications

References 20 publications

Effects of tyrosine-26 and tyrosine-64 nitration on the photoreactions of bacteriorhodopsin

Effects of tyrosine-26 and tyrosine-64 nitration on the photoreactions of bacteriorhodopsin

Chemical modification of tyrosine residues in p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens: assignment in sequence and catalytic involvement

Deprotonation of tyrosines in bacteriorhodopsin as studied by Fourier transform infrared spectroscopy with deuterium and nitrate labeling

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