Electron transfer reactions in Zn-substituted cytochrome P450cam

被引:18
作者
Furukawa, Y [1 ]
Ishimori, K [1 ]
Morishima, I [1 ]
机构
[1] Kyoto Univ, Dept Mol Engn, Grad Sch Engn, Kyoto 6068501, Japan
关键词
D O I
10.1021/bi000874y
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
We have investigated photoinduced electron transfer (ET) reactions between zinc-substituted cytochrome P450cam (ZnP450) and several inorganic reagents by using the laser flash photolysis method, to reveal roles of the electrostatic interactions in the regulation of the ET reactions. The laser pulse irradiation to ZnP450 yielded a strong reductant, the triplet excited state of ZnP450, (3)ZnP450*, which was able to transfer one electron to anionic redox partners, OsCl62- and Fe(CN)(6)(3-), with formation of the porphyrin pi-cation radical, ZnP450(+). In contrast, the ET reactions from (3)ZnP450* to cationic redox partners, such as Ru(NH3)(6)(3+) and Co(phen)(3)(3+), were not observed even in the presence of 100-fold excess of the oxidant. One of the possible interpretations for the preferential ET to the anionic redox partner is that the cationic patch on the P450cam surface, a putative interaction site for the anionic reagents, is located near the heme (less than 10 Angstrom from the heme edge), while the anionic surface is far from the heme moiety (more than 16 Angstrom from the heme edge), which would yield 8000-fold faster ET rates through the cationic patch. The ET rate through the anionic patch to the cationic partner would be substantially slower than that of the phosphorescence process in (3)ZnP450*, resulting in no ET reactions to the cationic reagents. These results demonstrate that the asymmetrical charge distribution on the protein surface is critical for the ET reaction in P450cam.
引用
收藏
页码:10996 / 11004
页数:9
相关论文
共 44 条
[1]   KINETIC-STUDIES ON REACTIONS OF IRON SULFUR PROTEINS - OXIDATION OF THE REDUCED FORM OF SPIRULINA-PLATENSIS [2FE-2S] FERREDOXIN WITH INORGANIC COMPLEXES [J].
ADZAMLI, IK ;
PETROU, A ;
SYKES, AG ;
RAO, KK ;
HALL, DO .
BIOCHEMICAL JOURNAL, 1983, 211 (01) :219-226
[2]   STRUCTURE OF ZINC-SUBSTITUTED CYTOCHROME-C - NUCLEAR-MAGNETIC-RESONANCE AND OPTICAL SPECTROSCOPIC STUDIES [J].
ANNI, H ;
VANDERKOOI, JM ;
MAYNE, L .
BIOCHEMISTRY, 1995, 34 (17) :5744-5753
[3]   NMR studies of putidaredoxin: associations of putidaredoxin with NADH-putidaredoxin reductase and cytochrome P450cam [J].
Aoki, M ;
Ishimori, K ;
Morishima, I .
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEIN STRUCTURE AND MOLECULAR ENZYMOLOGY, 1998, 1386 (01) :168-178
[4]   Roles of negatively charged surface residues of putidaredoxin in interactions with redox partners in P450cam monooxygenase system [J].
Aoki, M ;
Ishimori, K ;
Morishima, I .
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEIN STRUCTURE AND MOLECULAR ENZYMOLOGY, 1998, 1386 (01) :157-167
[5]   KINETICS AND MECHANISMS OF ELECTRON-TRANSFER BETWEEN BLUE COPPER PROTEINS AND ELECTRONICALLY EXCITED CHROMIUM AND RUTHENIUM POLYPYRIDINE COMPLEXES [J].
BRUNSCHWIG, BS ;
DELAIVE, PJ ;
ENGLISH, AM ;
GOLDBERG, M ;
MAYO, SL ;
SUTIN, N ;
GRAY, HB .
INORGANIC CHEMISTRY, 1985, 24 (23) :3743-3749
[6]  
BUTLER J, 1983, J BIOL CHEM, V258, P6400
[7]   REDOX PROTEIN ELECTRON-TRANSFER MECHANISMS - ELECTROSTATIC INTERACTIONS AS A DETERMINANT OF REACTION SITE IN C-TYPE CYTOCHROMES [J].
CHEDDAR, G ;
MEYER, TE ;
CUSANOVICH, MA ;
STOUT, CD ;
TOLLIN, G .
BIOCHEMISTRY, 1989, 28 (15) :6318-6322
[8]   PHOTOINDUCED ELECTRON-TRANSFER REACTIONS OF PLASTOCYANIN WITH THE TRIPLET-STATE OF ZINC MYOGLOBIN AND WITH THE ZINC MYOGLOBIN CATION-RADICAL - PROTEIN-PROTEIN ORIENTATION IN THE ABSENCE OF STRONG ELECTROSTATIC INTERACTIONS [J].
CHENG, J ;
ZHOU, JS ;
KOSTIC, NM .
INORGANIC CHEMISTRY, 1994, 33 (08) :1600-1606
[9]   EFFECTS OF NO2-MODIFICATION OF TYR83 ON THE REACTIVITY OF SPINACH PLASTOCYANIN WITH INORGANIC REDOX PARTNERS [FE(CN)6]3-/4- AND [CO(PHEN)3]3+/2+ [J].
CHRISTENSEN, HEM ;
ULSTRUP, J ;
SYKES, AG .
BIOCHIMICA ET BIOPHYSICA ACTA, 1990, 1039 (01) :94-102
[10]   SYNTHESIS AND PROPERTIES OF METAL-SUBSTITUTED MYOGLOBINS [J].
COWAN, JA ;
GRAY, HB .
INORGANIC CHEMISTRY, 1989, 28 (11) :2074-2078