Proton NMR studies of a metallothionein from Neurospora crassa: sequence-specific assignments by NOE measurements in the rotating frame.
Proton NMR studies of a metallothionein from Neurospora crassa: sequence-specific assignments by NOE measurements in the rotating frame.
复制标题
粗糙脉孢菌金属硫蛋白的质子核磁共振研究：通过旋转坐标系中的 NOE 测量进行序列特异性分配。
DOI：
10.1021/bi00433a038
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发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
Armitage,IM
中科院分区：
文献类型：
--
作者：
Malikayil,JA;Lerch,K;Armitage,IM
All potentially observable resonances were assigned except for thee-NH3 group of the C-terminal lysine. NOEs, when observed in the laboratory frame and at 500-MHz spectrometer frequency, were negligible in this protein due to the inherent rotational correlation time of the molecule. This difficulty was circumvented by measuring transverse NOEs in the rotating frame under spin-locking conditions. The observed pattern of NOEs reveals a marked absence of “regular” secondary structures in the protein. Thus, the stability of this metallothionein’s tertiary structure must arise primarily from its metal ligation. This appears to be a general feature of MTs since a general lack of extensive secondary structural elements was also observed in other metallothioneins.IN^ Ietallothionein from the fungus Neurospora crassa (NMT) is the smallest known metallothionein (MT). The protein contains 25 amino acid residues and has a molecular weight {Mr) of 2200. When isolated from mycelia that were exposed to high levels of Cu, NMT contains 6 mol of Cu-(I)/mol of protein in thiolate ligation to seven cysteine residues (Beltramini & Lerch 1986). The positions of all seven cysteines are identical with those of the first seven cysteines of the N-terminal region {ß domain) of hepatic mammalianMTs. However, NMT binds exclusively Cu (I) in its physiological state in contrast to the ß domain of mammalian MTs that are known to accommodate a variety of heavy metal ions (Kági & Vallee, 1961). Both NMR and X-ray diffraction methods have been used to elucidate the 3D structure of two mam-malian MTs (Frey et al., 1985; Braun et al., 1986; Vasak et al., 1987; Furey et al., 1986). A comparable wealth of structural information is not yet available for NMT or for MTs from lower organisms. With the objective to obtaining the same, we have conducted a two-dimensional NMR study
