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The role of specific amino acid resi...

Coleman, Matthew Adrian.

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The role of specific amino acid residues in the light-driven proton pump mechanism of bacteriorhodopsin.

Record Type:	Electronic resources : Monograph/item
Title/Author:	The role of specific amino acid residues in the light-driven proton pump mechanism of bacteriorhodopsin./
Author:	Coleman, Matthew Adrian.
Description:	187 p.
Notes:	Source: Dissertation Abstracts International, Volume: 57-11, Section: B, page: 6747.
Contained By:	Dissertation Abstracts International57-11B.
Subject:	Biology, Molecular. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9713658
ISBN:	0591213370

The role of specific amino acid residues in the light-driven proton pump mechanism of bacteriorhodopsin.
Coleman, Matthew Adrian.

The role of specific amino acid residues in the light-driven proton pump mechanism of bacteriorhodopsin. - 187 p.

Source: Dissertation Abstracts International, Volume: 57-11, Section: B, page: 6747.

Thesis (Ph.D.)--Boston University, 1997.

The membrane protein bacteriorhodopsin (bR) functions as a light-driven proton pump in the purple membrane of Halobacterium salinarium. Absorption of a photon by the bR retinylidene chromophone initiates a photocycle, which consists of metastable intermediates and results in the pumping of a proton across the purple membrane. Based on results from several laboratories, a mechanism for proton translocation has been proposed that involves a proton wire which spans between Asp-96 of bR and the retinylidene Schiff base and includes amino acid residues Asp-85, Asp-212, Arg-82, Thr-46, Thr-89, and Tyr-185. This model and the role of several of these amino acids in the proton pump mechanism of bR is investigated using molecular biology and spectroscopy. Amino acid substitutions for residues important for bR proton pumping and the expression of 28 different mutant proteins in Halobacterium salinarium are described. The results describe substitutions for residues that are up to 10 A away from the Schiff base, some of which affect the photocycle kinetics and the environment of the active site (e.g. Thr-46 and Asp-96). Furthermore, some residues in close proximity to the active site, (e.g. Tyr-57, Thr-89, Asp-85, Tyr-185, Asp-212 and Phe-219), confer stabilization of chromophore isomerization, modulate reprotonation of the Schiff base and/or control proton release into the extracellular medium. Possible alterations in the protein structure and/or function made spectroscopic interpretation of some mutants difficult. Therefore, assignment of specific functions to certain residues without altering the structure and/or function of the protein utilized the technique of site-directed isotope labeling and its application to bR. This technique allows the site-specific replacement of a single amino acid residue with an isotopically labeled analog of the same amino acid residue anywhere in the protein without changing the structure and/or function. Site-directed isotopic labeling of several tyrosine residues and assignment of vibrational bands in the Fourier transform infrared difference spectrum to one of these residues, Tyr-185, is described. These studies reveal information regarding the role of specific amino acids in the proton pump mechanism of bR.

ISBN: 0591213370Subjects--Topical Terms:

1017719
Biology, Molecular.

The role of specific amino acid residues in the light-driven proton pump mechanism of bacteriorhodopsin.
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100 1 $a Coleman, Matthew Adrian. $3 1927653
245 1 4 $a The role of specific amino acid residues in the light-driven proton pump mechanism of bacteriorhodopsin.
300 $a 187 p.
500 $a Source: Dissertation Abstracts International, Volume: 57-11, Section: B, page: 6747.
500 $a Major Professor: Dean Tolan.
502 $a Thesis (Ph.D.)--Boston University, 1997.
520 $a The membrane protein bacteriorhodopsin (bR) functions as a light-driven proton pump in the purple membrane of Halobacterium salinarium. Absorption of a photon by the bR retinylidene chromophone initiates a photocycle, which consists of metastable intermediates and results in the pumping of a proton across the purple membrane. Based on results from several laboratories, a mechanism for proton translocation has been proposed that involves a proton wire which spans between Asp-96 of bR and the retinylidene Schiff base and includes amino acid residues Asp-85, Asp-212, Arg-82, Thr-46, Thr-89, and Tyr-185. This model and the role of several of these amino acids in the proton pump mechanism of bR is investigated using molecular biology and spectroscopy. Amino acid substitutions for residues important for bR proton pumping and the expression of 28 different mutant proteins in Halobacterium salinarium are described. The results describe substitutions for residues that are up to 10 A away from the Schiff base, some of which affect the photocycle kinetics and the environment of the active site (e.g. Thr-46 and Asp-96). Furthermore, some residues in close proximity to the active site, (e.g. Tyr-57, Thr-89, Asp-85, Tyr-185, Asp-212 and Phe-219), confer stabilization of chromophore isomerization, modulate reprotonation of the Schiff base and/or control proton release into the extracellular medium. Possible alterations in the protein structure and/or function made spectroscopic interpretation of some mutants difficult. Therefore, assignment of specific functions to certain residues without altering the structure and/or function of the protein utilized the technique of site-directed isotope labeling and its application to bR. This technique allows the site-specific replacement of a single amino acid residue with an isotopically labeled analog of the same amino acid residue anywhere in the protein without changing the structure and/or function. Site-directed isotopic labeling of several tyrosine residues and assignment of vibrational bands in the Fourier transform infrared difference spectrum to one of these residues, Tyr-185, is described. These studies reveal information regarding the role of specific amino acids in the proton pump mechanism of bR.
590 $a School code: 0017.
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650 4 $a Biology, Microbiology. $3 1017734
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773 0 $t Dissertation Abstracts International $g 57-11B.
790 1 0 $a Tolan, Dean, $e advisor
790 $a 0017
791 $a Ph.D.
792 $a 1997
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9713658