Proton nuclear magnetic resonance studies of hemoglobins M Boston (alpha 58E7 His leads to Tyr) and M Milwaukee (beta 67E11 Val leads to Glu): spectral assignments of hyperfine-shifted proton resonances and of proximal histidine (E7) NH resonances to the
Proton nuclear magnetic resonance studies of hemoglobins M Boston (alpha 58E7 His leads to Tyr) and M Milwaukee (beta 67E11 Val leads to Glu): spectral assignments of hyperfine-shifted proton resonances and of proximal histidine (E7) NH resonances to the
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血红蛋白 M Boston（α 58E7 His 导致 Tyr）和 M Milwaukee（β 67E11 Val 导致 Glu）的质子核磁共振研究：超精细位移质子共振和近端组氨酸 (E7) NH 共振的光谱分配
作者：
Takahashi,S;Lin,AK;Ho,C
Tyr）和Hb M密尔沃基0367 E1 1 Val-Glu），以便将这些共振明确地归属于正常成人血红蛋白的α和β链。在Hb M Boston（a2+ 02）i中，α链的铁原子处于三价铁状态，而α链中的铁原子处于亚铁状态。另一方面，Hb M密尔沃基（α 2 O 2+）中α链的铁原子处于三价铁状态，而α链中的铁原子处于亚铁状态。由于未成对电子数的不同，铁和亚铁的超精细位移质子共振发生在光谱的不同区域。从D_（20）中脱氧Hb M Boston和Hb M密尔沃基的亚铁超精细位移质子共振的算术和导出的光谱，出现在从剩余HDO低场6到18 ppm之间，发现与正常成人脱氧血红蛋白的光谱基本相同。因此，在这个光谱区域的亚铁超精细位移质子共振的正常人成人脱氧血红蛋白的a和α链的分配已经完成。通过对这三种脱氧血红蛋白的光谱比较，确定了正常成人脱氧血红蛋白的α链和β链的近端组氨酸（E7）可交换NH共振峰。发现这些共振在H2O低场的58.5和71.0 ppm处重现。由于亚铁超精细位移质子共振化学位移的相似性，可以得出结论，未连接的Hb M Boston和Hb M Mil-waukee的亚铁血红素环境与正常人成人脱氧血红蛋白的亚铁血红素环境相似。另一方面，Hb M Boston和Hb M密尔沃基的铁超精细位移质子共振被发现不同于正常成人高铁血红蛋白。结果表明，这些血红蛋白中铁血红素的详细环境是不同的。脱氧型和蛋氨酸型血红蛋白（Hb）的质子核磁共振（NMR）1谱显示出几个远离大多数抗磁共振的特征共振。它们产生于铁原子的未成对电子之间的超精细相互作用。1980年5月12日收到。由美国国立Flealth研究所（HL-24525）和美国国家科学基金会（PCM 78-25818）的研究赠款支持。匹兹堡的核磁共振设备得到了美国国立卫生研究院的研究资助（RR-00292）。本文的一部分发表在1979年2月25日至28日在佐治亚州亚特兰大举行的生物物理学会年会上，以及1980年4月13日至18日在弗吉尼亚州艾尔利的艾尔利大厦举行的铁和蛋白质在氧和电子传递中的相互作用研讨会上。现住址：日本东京，东京大学生物物理和生物化学系。以及血红素上的质子基团和/或α和β链附近的氨基酸残基。超精细位移共振有两种类型，费米接触位移共振和赝接触位移共振。[For最近关于血红素蛋白中超精细位移质子共振的讨论，参见Ho et al. 1978年，他的作品被引用。这些共振对血红素基团的构象和铁原子的电子自旋状态敏感（Kurland等人，1968; Lindstrom等人，1972; Ho等人，1973，1978; Fung等人，1976，1977; Viggiano和Ho，1979; Viggiano等人，1979年）。一些
Tyr) and Hb M Milwaukee 0367El 1 Val—Glu), in order to make a definite assignment of these resonances to the a and ß chains of normal human adult hemoglobin. In Hb M Boston (a2+ 02) i the iron atoms of the a chains are in the ferric state, while those in the ß chains are in the ferrous state. On the other hand, the iron atoms of the ß chains in Hb M Milwaukee (a202+) are in the ferric state, while those in the a chains are in the ferrous state. Due to the difference in the number of unpaired electrons, ferric and ferrous hyperfineshifted proton resonances occur in different regions of the spectrum. The spectrum derived from the arithmetical sum of the ferrous hyperfine-shifted proton resonances of deoxy-Hb M Boston and Hb M Milwaukee in D20, which appear be-tween 6 and 18 ppm downfield from residual HDO, is found to be essentially identical with thatof normal human adult deoxyhemoglobin. Thus, the assignment of the ferrous hyperfine-shifted proton resonances in this spectral region to the a and ß chains of normal human adult deoxyhemoglobin has been accomplished. By means of the spectral comparison of these three hemoglobins in the deoxy form, an assignment of the proximal histidine (E7) exchangeable NH resonances to the a and ß chains of normalhuman adult deoxyhemoglobin has also been established. These resonances are found re-spectively at 58.5 and 71.0 ppm downfieldfrom H20. Because of the similarity of the chemical shifts of ferrous hyperfine-shifted proton resonances, it is concluded that the ferrous heme environments of unligated Hb M Boston and Hb M Mil-waukee are similar to those of normal human adult deoxy-hemoglobin. On the other hand, the ferric hyperfine-shifted proton resonances of Hb M Boston and Hb M Milwaukee are found to be different from those of normal human adult methemoglobin. The results suggest that the detailed environments of the ferric hemes in these hemoglobins are dif-ferent. e proton nuclear magnetic resonance(NMR) 1 spectra of hemoglobin (Hb) in the deoxy and met forms show several characteristic resonances which are remote from the majority of diamagnetic resonances. They arise from the hyperfine interactions between the unpaired electrons of the iron atoms f From the Department of Biological Sciences, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, Pennsylvania15213. Received May 12, 1980. Supported by research grants from the National Institutes of Flealth (HL-24525) and the National Science Foundation (PCM 78-25818). The NMR Facility in Pittsburgh is supported by a research grantfrom the National Institutes of Health (RR-00292). Part of this paper was presented at the Annual Meeting of the Biophysical Society, Atlanta, GA, Feb 25-28, 1979, and the Symposium on the Interaction between Iron and Proteins in Oxygen and Electron Transport, Airlie House, Airlie, VA, April 13-18, 1980.* Present address: Department of Biophysics and Biochemistry, University of Tokyo, Tokyo, Japan. and the proton groups on the hemes and/or the nearby amino acid residues of the a and ß chains. There are two types of hyperfine-shifted resonances, Fermi contactand pseudocontact shifted resonances.[For a recent discussion on hyperfine-shifted proton resonances in heme proteins, see Ho et al.(1978) and the references cited therein.] These resonances are sen-sitive to the conformation of the heme groups andto the electronic spin state of the iron atoms (Kurland et al., 1968; Lindstrom et al., 1972; Ho et al., 1973, 1978; Fung et al., 1976, 1977; Viggiano & Ho, 1979; Viggiano et al., 1979). A number