Only water‐exposed carboxyl groups are protonated during the transition to the cation‐free blue bacteriorhodopsin

FEBS Letters

Siebert, Friedrich¹  Hess, Benno²  Ganter, Ulrich M.¹  Gerwert, Klaus² 

[1] Institut für Biophysik und Strahlenbiologie, Universität Freiburg, Albertstr. 23, 7800 Freiburg, FRG;Max-Planck-Institut für Ernährungsphysiologie, Rheinlanddamm 201, 4600 Dortmund, FRG

关键词: FTIR;    Cation depletion;    Blue bacteriorhodopsin;    Surface potential;    Carboxyl group;    Protonation change;   

DOI  :  10.1016/0014-5793(87)81461-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

FTIR (Fourier-transform-infrared) difference spectra between cation-free blue and purple bacteriorhodopsin were recorded. The results indicate that during the blue to purple transition no isomerization of the chromophore takes place. It is further observed that approx. 14 water-exposed carboxyl groups ofamino acids are protonated in blue bacteriorhodopsin. The groups were deprotonated during the blue to purple transition. Protonation of carboxyl groups in the interior of the protein, which are not accessible to water, can be excluded.

【 授权许可】

Unknown