Axial ligation and stoichiometry of heme centers in adrenal cytochrome b561

被引:21
作者
Kamensky, Yury [1 ]
Liu, Wen
Tsai, Ah-Lim
Kulmacz, Richard J.
Palmer, Graham
机构
[1] Rice Univ, Dept Biochem & Cell Biol, Houston, TX 77251 USA
[2] Univ Texas, Hlth Sci Ctr, Dept Internal Med, Houston, TX 77030 USA
关键词
D O I
10.1021/bi700054g
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Cytochrome (cyt) b(561) transports electrons across the membrane of chromaffin granules (CG) present in the adrenal medulla, supporting the biosynthesis of norepinephrine in the CG matrix. We have conducted a detailed characterization of cyt b(561) using electron paramagnetic resonance (EPR) and optical spectroscopy on the wild-type and mutant forms of the cytochrome expressed in insect cells. The g(z) = 3.7 (low-potential heme) and g(z) = 3.1 (high-potential heme) signals were found to represent the only two authentic hemes of cyt b(561); models that propose smaller or greater amounts of heme can be ruled out. We identified the axial ligands to hemes in cyt b(561) by mutating four conserved histidines (His54 and His122 at the matrix-side heme center and His88 and His161 at the cytoplasmic-side heme center), thus confirming earlier structural models. Single mutations of any of these histidines produced a constellation of spectroscopic changes that involve not one but both heme centers. We hypothesize that the two hemes and their axial ligands in cyt b(561) are integral parts of a structural unit that we term the "kernel". Histidine to glutamine substitutions in the cytoplasmic-side heme center but not in the matrix-side heme center led to the retention of a small fraction of the low-potential heme with g(z) = 3.7. We provisionally assign the low-potential heme to the matrix side of the membrane; this arrangement suggests that the membrane potential modulates electron transport across the CG membrane.
引用
收藏
页码:8647 / 8658
页数:12
相关论文
共 50 条
[21]   Structure-function relations in cytochrome b561 proteins [J].
Berczi, A. ;
Laskay, K. ;
Zimanyi, L. .
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS, 2015, 44 :S51-S51
[22]   Enzymatic control of electron transfer illustrated by cytochrome b561 [J].
Njus, D ;
Kelley, PM ;
Kipp, BH ;
Schlegel, HB .
BIOPHYSICAL JOURNAL, 1998, 74 (02) :A79-A79
[23]   Selective perturbation of the intravesicular heme center of cytochrome b561 by cysteinyl modification with 4,4′-dithiodipyridine [J].
Takeuchi, F ;
Hori, H ;
Tsubaki, M .
JOURNAL OF BIOCHEMISTRY, 2005, 138 (06) :751-762
[24]   Properties of two distinct heme centers of cytochrome b561 from bovine chromaffin vesicles studied by EPR, resonance Raman, and ascorbate reduction assay [J].
Takeuchi, F ;
Hori, H ;
Obayashi, E ;
Shiro, Y ;
Tsubaki, M .
JOURNAL OF BIOCHEMISTRY, 2004, 135 (01) :53-64
[25]   Localization of an ascorbate-reducible cytochrome b561 in the plant tonoplast [J].
Griesen, D ;
Su, D ;
Bérczi, A ;
Asard, H .
PLANT PHYSIOLOGY, 2004, 134 (02) :726-734
[26]   An ascorbate-reducible cytochrome b561 is localized in macrophage lysosomes [J].
Zhang, De-liang ;
Su, Dan ;
Berczi, Alajos ;
Vargas, Amy ;
Asard, Han .
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS, 2006, 1760 (12) :1903-1913
[27]   Structural and functional roles of histidine residues in cytochrome b561, a transmembrane electron transporter in adrenal chromaffin granules [J].
Kamensky, Y. ;
Liu, W. ;
Palmer, G. ;
Kulmacz, R. J. .
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 2006, :185-186
[28]   Characterization of a vacuolar cytochrome b561 by redox titration and spectrum analysis [J].
Zimanyi, Laszlo ;
Berczi, Alajos .
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS, 2011, 40 :186-186
[29]   nemy encodes a cytochrome b561 that is required for Drosophila learning and memory [J].
Iliadi, Konstantin G. ;
Avivi, Aaron ;
Iliadi, Natalia N. ;
Knight, David ;
Korol, Abraham B. ;
Nevo, Eviatar ;
Taylor, Paul ;
Moran, Michael F. ;
Kamyshev, Nikolai G. ;
Boulianne, Gabrielle L. .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2008, 105 (50) :19986-19991
[30]   PURIFICATION OF CYTOCHROME B-561 - INTEGRAL HEME PROTEIN OF ADRENAL CHROMAFFIN GRANULE MEMBRANE [J].
SILSAND, T ;
FLATMARK, T .
BIOCHIMICA ET BIOPHYSICA ACTA, 1974, 359 (02) :257-266