DISTAL AND PROXIMAL LIGAND INTERACTIONS IN HEME-PROTEINS - CORRELATIONS BETWEEN C-O AND FE-C VIBRATIONAL FREQUENCIES, O-17 AND C-13 NUCLEAR-MAGNETIC-RESONANCE CHEMICAL-SHIFTS, AND O-17 NUCLEAR-QUADRUPOLE COUPLING-CONSTANTS IN (CO)-O-17-LABELED AND (CO)-C-13-LABELED SPECIES
DISTAL AND PROXIMAL LIGAND INTERACTIONS IN HEME-PROTEINS - CORRELATIONS BETWEEN C-O AND FE-C VIBRATIONAL FREQUENCIES, O-17 AND C-13 NUCLEAR-MAGNETIC-RESONANCE CHEMICAL-SHIFTS, AND O-17 NUCLEAR-QUADRUPOLE COUPLING-CONSTANTS IN (CO)-O-17-LABELED AND (CO)-C-13-LABELED SPECIES
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DOI：
10.1021/bi00223a007
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发表时间：
1991-03-05
期刊：
影响因子：
2.9
通讯作者：
OLDFIELD, E
中科院分区：
文献类型：
--
作者：
PARK, KD;GUO, K;OLDFIELD, E
我们获得了多种 C-17 O 标记血红蛋白的氧 17 核磁共振 (NMR) 谱，包括抹香鲸 (Physeter catodon) 肌红蛋白、两种合成抹香鲸肌红蛋白突变体 (His E7 --> Val E7; His E7 --> Phe E7)、成人血红蛋白、兔 (Oryctolagus cuniculus) 血红蛋白、辣根 (Cochlearia armacia)过氧化物酶 (E.C. 1.11.1.7) 同工酶 A 和 C，以及 Caldariomyces fumago 氯过氧化物酶 (E.C. 1.11.1.10)，在某些情况下作为 pH 的函数，并确定了它们的各向同性 O-17 NMR 化学位移 delta-i 和自旋晶格弛豫时间 T1。 我们还在溶液和固态的栅栏卟啉[5,10,15,20-四(α,α,α,α-新酰胺基苯基)卟啉]铁(II)(1-MeIm)CO上获得了类似的结果。我们的结果表明，红外 C-O 振动频率 nu-(C-O) 和 delta-i 之间、nu(C-O) 和 O-17 核四极耦合常数（e2qQ/h，从 T1 导出）之间以及 e2qQ/h 和 delta-i 之间具有良好的相关性。 结合其他人在 (CO)-C-13 标记蛋白质的 C-13 NMR 上的工作，我们发现 delta-i(C-13) 和 nu(Fe-C) 之间存在极好的相关性，我们的结果表明 IR 和 NMR 测量反映了相同的相互作用，这被认为主要是从 Fe d 到 CO-pi-* 轨道的 pi 背键合程度，如前所述 [Li, X.-Y., & Spiro, T. G. (1988) J. Am。化学。苏克。 110、6024]。 讨论了多种物种和突变体中远端血红素残基（组氨酸、谷氨酰胺、精氨酸和可能的赖氨酸）的局部电荷场对这种相互作用的调节，如 NMR 和 IR 测量所反映的那样，以及半胱氨酸作为近端血红素配体的作用。
We have obtained the oxygen-17 nuclear magnetic resonance (NMR) spectra of a variety of C-17 O-labeled heme proteins, including sperm whale (Physeter catodon) myoglobin, two synthetic sperm whale myoglobin mutants (His E7 --> Val E7; His E7 --> Phe E7), adult human hemoglobin, rabbit (Oryctolagus cuniculus) hemoglobin, horseradish (Cochlearia armoracia) peroxidase (E.C. 1.11.1.7) isoenzymes A and C, and Caldariomyces fumago chloroperoxidase (E.C. 1.11.1.10), in some cases as a function of pH, and have determined their isotropic O-17 NMR chemical shifts, delta-i, and spin-lattice relaxation times, T1. We have also obtained similar results on a picket fence porphyrin, [5,10,15,20-tetrakis(alpha,alpha,alpha,alpha-pivalamidophenyl)porphyrinato]iron(II)(1-MeIm)CO, both in solution and in the solid state. Our results show an excellent correlation between the infrared C-O vibrational frequencies, nu-(C-O), and delta-i, between nu(C-O) and the O-17 nuclear quadrupole coupling constant (e2qQ/h, derived from T1), and as expected between e2qQ/h and delta-i. Taken together with the work of others on the C-13 NMR of (CO)-C-13-labeled proteins, where we find an excellent correlation between delta-i(C-13) and nu(Fe-C), our results suggest that IR and NMR measurements reflect the same interaction, which is thought to be primarily the degree of pi-back-bonding from Fe d to CO-pi-* orbitals, as outlined previously [Li, X.-Y., & Spiro, T. G. (1988) J. Am. Chem. Soc. 110, 6024]. The modulation of this interaction by the local charge field of the distal heme residue (histidine, glutamine, arginine, and possibly lysine) in a variety of species and mutants, as reflected in the NMR and IR measurements, is discussed, as is the effect of cysteine as the proximal heme ligand.