Preliminary X-ray diffraction analysis of the cytoplasmic N-terminal domain of the Na/HCO3 cotransporter NBCe1-A.
Preliminary X-ray diffraction analysis of the cytoplasmic N-terminal domain of the Na/HCO3 cotransporter NBCe1-A.
复制标题
DOI：
10.1107/s1744309106015181
复制
发表时间：
2006-06
期刊：
影响因子：
--
通讯作者：
H. Gill;W. Boron
中科院分区：
文献类型：
--
作者：
H. Gill;W. Boron
Na+偶联HCO_3协同转运蛋白NBCe 1-A（NtNBCe 1）的N端胞质结构域与近端肾小管酸中毒有关。在先前的重组NtNBCe 1纯化研究中，在次优蛋白浓度（<1 mg ml（-1））下晶体生长产生小的单个菱形晶体，衍射较差。在本研究中，通过将蛋白质浓度增加50倍，晶体尺寸增加一倍，耐用性也得到改善。晶体退火使晶体适合于X射线衍射。晶体属于空间群P3（1）21或具有伪P3（1）21对称性的P3（1），晶胞参数a = 51.7，B = 51.7，c = 200.6 A，α = β = 90，γ = 120度，并且X射线衍射分辨率为3.0 A。计算的马修斯数为1.9 A3 Da（-1），在不对称单元中有两个分子量约为83 kDa的单体。分子置换包装解决方案表明，分子通过结构域交换机制形成二聚体。
The N-terminal cytoplasmic domain of the Na+-coupled HCO_3- cotransporter NBCe1-A (NtNBCe1) has been linked with proximal renal tubular acidosis. In a previous purification study of recombinant NtNBCe1, crystal growth at a suboptimal protein concentration (<1 mg ml(-1)) yielded small single diamond-shaped crystals that diffracted poorly. In the present study, by increasing the protein concentration 50-fold, the crystal size was doubled and robustness was also improved. Crystal annealing made the crystals suitable for X-ray diffraction. The crystals either belong to space group P3(1)21 or P3(1) with pseudo P3(1)21 symmetry, with unit-cell parameters a = 51.7, b = 51.7, c = 200.6 A, alpha = beta = 90, gamma = 120 degrees , and diffract X-rays to 3.0 A resolution. The calculated Matthews number is 1.9 A3 Da(-1), with two monomers of molecular weight approximately 83 kDa in the asymmetric unit. The molecular- replacement packing solution shows that the molecules form dimers by a domain-swapping mechanism.