Proton nuclear magnetic resonance spectroscopy and ligand binding dynamics of the Escherichia coli L-arabinose binding protein.
Proton nuclear magnetic resonance spectroscopy and ligand binding dynamics of the Escherichia coli L-arabinose binding protein.
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大肠杆菌 L-阿拉伯糖结合蛋白的质子核磁共振波谱和配体结合动力学。
DOI：
10.1021/bi00538a035
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发表时间：
1982
期刊：
影响因子：
2.9
通讯作者：
Hogg,RW
中科院分区：
文献类型：
--
作者：
Clark,AF;Gerken,TA;Hogg,RW
艾博特·F Clark，* 托马斯A. Gerken和RobertW. Hogg* 摘要：利用核磁共振氢谱（NMR）研究了大肠杆菌L-阿拉伯糖结合蛋白（ABP）。当ABP结合其天然配体L-阿拉伯糖时，会发生明显的光谱变化，其中涉及芳环电流移动甲基、本体甲基、亚甲基、芳族和酰胺质子光谱区域的共振。如果L-阿拉伯糖在氧化氘透析之前与ABP结合，则可以“保护”几个酰胺共振免于氘交换。的基础上的pH值的依赖性，他们的化学位移，两个低场共振已被暂时分配到C2质子的三个组氨酸存在于ABP。这些组氨酰残基的pK值为8.0和8.6，这支持它们参与晶体学分析中早期观察到的离子相互作用。一种组氨酰（histidyl）β-内酰胺酶阴性肠道细菌含有许多周质结合蛋白，这些蛋白对于许多糖、氨基酸和离子的高亲和力转运是必需的（Boos，1974）。这些分子中有几种在细菌趋化过程中也充当受体（桤木，1975; Koshland，1977）。结合蛋白通过渗透压休克处理（Neu和Heppel，1965）从周质释放，伴随着转运活性的丧失，并具有10-6-10- 8 M的高亲和力和对配体结合的特异性。在结合配体时，这些周质结合蛋白必须向特定的整合膜蛋白发出信号，表明它们准备参与这些指定的过程。在几种情况下，当周质结合蛋白结合其各自的配体时，已经报道了构象变化（Boos & Gordon，1971; Boos，1972; Langridge等人，1970; Weiner & Heppel，1971; McGowan等人，1974; Szmeleman等人，1976; Kreishman等人，1973; Robertson等人，1977年; Manuck& Ho，
Abbot F. Clark,* Thomas A. Gerken, and RobertW. Hogg* abstract: The L-arabinose binding protein (ABP) from Escherichia coli was studied by proton nuclear magnetic resonance spectroscopy (NMR). Distinct spectral changes occur when ABP binds its natural ligand, L-arabinose, which involve resonances in the aromatic ring current shifted methyl, bulk methyl, methylene, aromatic, and amide proton regions of the spectra. Several amide resonances can be “protected” from deuterium exchange if L-arabinose is bound to ABP prior to deuterium oxide dialysis. On the basis of the pH dependence of their chemical shifts, two low-field resonances have been tentatively assigned to C2 protons of two of the three histidines present in ABP. These histidyl residues have pK values of 8.0 and 8.6 which support their involvement in ionic interactions observed earlier in the crystallographic analysis. One histidyl (jram-negative enteric bacteria contain a number of periplasmic binding proteins which are essential for the high-af-finity transport of many sugars, amino acids, and ions (Boos, 1974). Several of these molecules also serve as receptors during bacterial chemotaxis (Alder, 1975; Koshland, 1977). Binding proteins are released from the periplasm by osmotic shock treatment (Neu & Heppel, 1965) with concomitant loss of transport activity and have a high affinity s of 10-6—10-8M) and specificity for ligand binding. Upon binding ligand, such periplasmic binding proteins must signal specific integral membrane proteins that they are ready to participate in these designated processes. In several cases, conformational changes have been reported when periplasmic binding proteins bind their respective ligand (Boos & Gordon, 1971; Boos, 1972; Langridge et al., 1970; Weiner & Heppel, 1971; McGowan et al., 1974; Szmeleman et al., 1976; Kreishman et al., 1973; Robertson et al., 1977; Manuck& Ho,