The role of porphyrin peripheral substituents in determining the reactivities of ferrous nitrosyl species

被引:20
作者
Amanullah, Sk [1 ]
Dey, Abhishek [1 ]
机构
[1] Indian Assoc Cultivat Sci, Sch Chem Sci, 2A & 2B Raja SC Mullick Rd, Kolkata 700032, India
关键词
REDUCTASE MODEL COMPOUNDS; CYTOCHROME CD(1) NITRITE; PI-CATION RADICALS; DISSIMILATORY NITRITE; ELECTRONIC-STRUCTURE; OXIDE REDUCTASE; REDOX CHEMISTRY; HYDRIDE ATTACK; HEME-NITROSYLS; D(1) HEME;
D O I
10.1039/d0sc01625j
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Ferrous nitrosyl {FeNO}(7)species is an intermediate common to the catalytic cycles of Cd1NiR and CcNiR, two heme-based nitrite reductases (NiR), and its reactivity varies dramatically in these enzymes. The former reduces NO(2)(-)to NO in the denitrification pathway while the latter reduces NO(2)(-)to NH(4)(+)in a dissimilatory nitrite reduction. With very similar electron transfer partners and heme based active sites, the origin of this difference in reactivity has remained unexplained. Differences in the structure of the hemed(1)(Cd1NiR), which bears electron-withdrawing groups and has saturated pyrroles, relative to hemec(CcNiR) are often invoked to explain these reactivities. A series of iron porphyrinoids, designed to model the electron-withdrawing peripheral substitution as well as the saturation present in hemed(1)in Cd1NiR, and their NO adducts were synthesized and their properties were investigated. The data clearly show that the presence of electron-withdrawing groups (EWGs) and saturated pyrroles together in a synthetic porphyrinoid (FeDEsC) weakens the Fe-NO bond in {FeNO}(7)adducts along with decreasing the bond dissociation free energies (BDFENH) of the {FeHNO}(8)species. The EWG raises theE degrees of the {FeNO}(7/8)process, making the electron transfer (ET) facile, but decreases the pK(a)of {FeNO}(8)species, making protonation (PT) difficult, while saturation has the opposite effect. The weakening of the Fe-NO bonding biases the {FeNO}(7)species of FeDEsC for NO dissociation, as in Cd1NiR, which is otherwise set-up for a proton-coupled electron transfer (PCET) to form an {FeHNO}(8)species eventually leading to its further reduction to NH4+.
引用
收藏
页码:5909 / 5921
页数:13
相关论文
共 78 条
[41]   ELECTROCHEMICAL AND SPECTRAL CHARACTERIZATION OF IRON MONONITROSYL AND DINITROSYL PORPHYRINS [J].
LANCON, D ;
KADISH, KM .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1983, 105 (17) :5610-5617
[42]   The HNO adduct of myoglobin: Synthesis and characterization [J].
Lin, R ;
Farmer, PJ .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (10) :2393-2394
[43]   Refined synthesis of 5-substituted dipyrromethanes [J].
Littler, BJ ;
Miller, MA ;
Hung, CH ;
Wagner, RW ;
O'Shea, DF ;
Boyle, PD ;
Lindsey, JS .
JOURNAL OF ORGANIC CHEMISTRY, 1999, 64 (04) :1391-1396
[44]   ELECTROCHEMISTRY OF NITRITE REDUCTASE MODEL COMPOUNDS .5. ELECTROCHEMISTRY AND SPECTROELECTROCHEMISTRY OF IRON PORPHINONE, PORPHINDIONE AND ISOBACTERIOCHLORIN COMPLEXES [J].
LIU, YM ;
RYAN, MD .
INORGANICA CHIMICA ACTA, 1994, 225 (1-2) :57-66
[45]   THE ELECTROCHEMICAL REDUCTION OF IRON PORPHYRIN NITROSYLS IN THE PRESENCE OF WEAK ACIDS [J].
LIU, YM ;
RYAN, MD .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1994, 368 (1-2) :209-219
[46]   Electrochemistry of nitrite reductase model compounds .6. Voltammetric and spectroelectrochemical studies of iron(II) nitrosyl complexes with porphyrins, hydroporphyrins and porphinones [J].
Liu, YM ;
DeSilva, C ;
Ryan, MD .
INORGANICA CHIMICA ACTA, 1997, 258 (02) :247-255
[47]   How Biology Handles Nitrite [J].
Maia, Luisa B. ;
Moura, Jose J. G. .
CHEMICAL REVIEWS, 2014, 114 (10) :5273-5357
[48]   INFRARED STUDY OF NO BONDING TO HEME-B AND HEMOGLOBIN-A - EVIDENCE FOR INOSITOL HEXAPHOSPHATE INDUCED CLEAVAGE OF PROXIMAL HISTIDINE TO IRON BONDS [J].
MAXWELL, JC ;
CAUGHEY, WS .
BIOCHEMISTRY, 1976, 15 (02) :388-396
[49]   CONTRACTED GAUSSIAN-BASIS SETS FOR MOLECULAR CALCULATIONS .1. 2ND ROW ATOMS, Z=11-18 [J].
MCLEAN, AD ;
CHANDLER, GS .
JOURNAL OF CHEMICAL PHYSICS, 1980, 72 (10) :5639-5648
[50]  
Moreno-Vivián C, 1999, J BACTERIOL, V181, P6573