3-DIMENSIONAL STRUCTURE OF INFLUENZA-A N9 NEURAMINIDASE AND ITS COMPLEX WITH THE INHIBITOR 2-DEOXY 2,3-DEHYDRO-N-ACETYL NEURAMINIC ACID
3-DIMENSIONAL STRUCTURE OF INFLUENZA-A N9 NEURAMINIDASE AND ITS COMPLEX WITH THE INHIBITOR 2-DEOXY 2,3-DEHYDRO-N-ACETYL NEURAMINIC ACID
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DOI：
10.1006/jmbi.1993.1461
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发表时间：
1993-08-20
影响因子：
5.6
通讯作者：
AIR, GM
中科院分区：
文献类型：
--
作者：
BOSSARTWHITAKER, P;CARSON, M;AIR, GM
我们在这里提出的神经氨酸酶（E.C.）的三维结构。3.2.1.18）从流感病毒A/Tern/Australia/G70 c/75（N9）中分离的神经氨酸酶的结构，以及与抑制剂2-脱氧-2，3-脱氢-N-乙酰神经氨酸（DANA）复合的神经氨酸酶的结构。天然和抑制剂复合物晶体是同晶型的，属于空间群I432，晶胞尺寸为183·78 nm。天然酶结构和抑制剂复合物结构已分别在2.5 μ m和2.8 μ m分辨率下得到细化，天然酶的晶体学R因子值为0.193，抑制剂复合物的晶体学R因子值为0.179。目前的酶模型包括387个氨基酸残基，其构成不对称单元。键长和键角的均方根偏差分别为0.013 °和1.6 °。神经氨酸酶（NA）从病毒上蛋白水解下来后，保留了完整的酶和抗原活性，是一个边长为90 °，最大深度为60 °的盒状四聚体。NA四聚体由通过圆形4重对称性相关的晶体学等效单体组成。每个单体折叠成六个反平行的四股β折叠。二级结构组成为500% β-折叠。剩余的50%的残基形成24个链连接环或转角。NA与过渡态类似物DANA的复合物的结构使我们能够确定和表征酶催化的位点。结合抑制剂的质量中心距离四聚体的4倍轴32 Å，位于直径16 Å、深度8至10 Å的浅弹坑的末端。有12个氨基酸残基直接结合DANA，另外6个保守氨基酸排列在活性位点口袋中。神经氨酸酶抑制剂复合物提供了一个三维模型，将用于进一步了解酶水解和帮助设计特定的，抗神经氨酸酶的抗病毒化合物。
We present here the three-dimensional structure of neuraminidase (E.C. 3.2.1.18) from influenza virus A/Tern/Australia/G70c/75 (N9), determined by the method of multiple isomorphous replacement, and the structure of the neuraminidase complexed with an inhibitor, 2-deoxy-2,3-dehydro-N-acetyl neuraminic acid (DANA). Native and inhibitor complex crystals are isomorphous and belong to space groupI432 with unit cell dimensions of 183·78 Å. The native enzyme structure and the inhibitor complex structure have been refined at 2·5 Å and 2·8 Å resolution, respectively, with crystallographicR-factor values of 0·193 for the native enzyme, and 0·179 for the inhibitor complex. The current enzyme model includes 387 amino acid residues which comprise the asymmetric unit. The root-mean-square deviation from ideal values is 0·013 Å for bond lengths and 1·6° for bond angles.The neuraminidase (NA), as proteolytically cleaved from the virus, retains full enzymatic and antigenic activity, and is a box-shaped tetramer with edge lengths of 90 Å and a maximal depth of 60 Å. The NA tetramers are composed of crystallographically equivalent monomers related by circular 4-fold symmetry. Each monomer folds into six antiparallel β-sheets of four strands. The secondary structure composition is 500% β-sheet. The remaining 50% of the residues form 24 strand connecting loops or turns. One of the loops contains a small α-helix.The structure of the complex of NA with DANA, a transition state analog, has enabled us to identify and characterize the site of enzyme catalysis. The center of mass of bound inhibitor is 32 Å from the 4-fold axis of the tetramer, lodged at the end of a shallow crater of diameter 16 Å with a depth of 8 to 10 Å. There are 12 amino acid residues that directly bind DANA, with a further six conserved amino acids lining the active site pocket. The neuraminidase inhibitor complex provides a three-dimensional model which will be used to further the understanding of enzymatic hydrolysis and aid the design of specific, anti-neuraminidase antiviral compounds.