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Proton transfer reactions in donor site mutants of ESR, a retinal protein from Exiguobacterium sibiricum.
Petrovskaya, Lada E; Lukashev, Evgeniy P; Siletsky, Sergey A; Imasheva, Eleonora S; Wang, Jennifer M; Mamedov, Mahir D; Kryukova, Elena A; Dolgikh, Dmitriy A; Rubin, Andrei B; Kirpichnikov, Mikhail P; Balashov, Sergei P; Lanyi, Janos K.
Afiliação
  • Petrovskaya LE; Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia. Electronic address: lpetr65@yahoo.com.
  • Lukashev EP; M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia.
  • Siletsky SA; Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russian Federation. Electronic address: siletsky@genebee.msu.su.
  • Imasheva ES; Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
  • Wang JM; Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
  • Mamedov MD; Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russian Federation.
  • Kryukova EA; Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia; Emanuel Institute of Biochemical Physics, Kosygina str., 4, Moscow 119334, Russia.
  • Dolgikh DA; Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia; M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia; Emanuel Institute of Biochemical Physics, Kosygina
  • Rubin AB; M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia.
  • Kirpichnikov MP; Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia; M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia.
  • Balashov SP; Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA. Electronic address: balashov@uci.edu.
  • Lanyi JK; Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
J Photochem Photobiol B ; 234: 112529, 2022 Sep.
Article em En | MEDLINE | ID: mdl-35878544
Light-driven proton transport by microbial retinal proteins such as archaeal bacteriorhodopsin involves carboxylic residues as internal proton donors to the catalytic center which is a retinal Schiff base (SB). The proton donor, Asp96 in bacteriorhodopsin, supplies a proton to the transiently deprotonated Schiff base during the photochemical cycle. Subsequent proton uptake resets the protonated state of the donor. This two step process became a distinctive signature of retinal based proton pumps. Similar steps are observed also in many natural variants of bacterial proteorhodopsins and xanthorhodopsins where glutamic acid residues serve as a proton donor. Recently, however, an exception to this rule was found. A retinal protein from Exiguobacterium sibiricum, ESR, contains a Lys residue in place of Asp or Glu, which facilitates proton transfer from the bulk to the SB. Lys96 can be functionally replaced with the more common donor residues, Asp or Glu. Proton transfer to the SB in the mutants containing these replacements (K96E and K96D/A47T) is much faster than in the proteins lacking the proton donor (K96A and similar mutants), and in the case of K96D/A47T, comparable with that in the wild type, indicating that carboxylic residues can replace Lys96 as proton donors in ESR. We show here that there are important differences in the functioning of these residues in ESR from the way Asp96 functions in bacteriorhodopsin. Reprotonation of the SB and proton uptake from the bulk occur almost simultaneously during the M to N transition (as in the wild type ESR at neutral pH), whereas in bacteriorhodopsin these two steps are well separated in time and occur during the M to N and N to O transitions, respectively.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Prótons / Bacteriorodopsinas Idioma: En Ano de publicação: 2022 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Prótons / Bacteriorodopsinas Idioma: En Ano de publicação: 2022 Tipo de documento: Article