High-resolution structure of exo-arabinanase from Penicillium chrysogenum.
High-resolution structure of exo-arabinanase from Penicillium chrysogenum.
复制标题
来自产黄青霉的外切阿拉伯聚糖酶的高分辨率结构。
DOI：
10.1107/s0907444911006299
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
他
中科院分区：
文献类型：
--
作者：
Sogabe Y;Kitatani T;他
Arabinanase Abnx from Penicillium chrysogenum 31B, which belongs to the GH93 family, releases arabinobiose from the nonreducing terminus of α-1,5-l-arabinan, which is distributed in the primary cell walls of higher plants. Crystal structures of Abnx and of its complex with arabinobiose were determined at the high resolutions of 1.14 Å to an Rwork of 10.7% (Rfree = 12.8%) and 1.04 Å to an Rwork of 10.4% (Rfree = 12.5%). Abnx has a six-bladed β-propeller fold with a typical ring-closure mode called `Velcro', in which the last four-stranded β-sheet is completed by the incorporation of a strand from the N-terminus. Catalytic residues which act as a nucleophile and an acid/base were proposed from the structures and confirmed by site-directed mutagenesis. The substrate-binding groove is enclosed at one end by two residues, Glu64 and Tyr66, which contribute to the recognition of the nonreducing chain end of the polysaccharide. A comparison with the related enzyme Arb93A which has a quite similar overall structure suggested that Abnx has different mechanisms to funnel substrates to the active site and/or to stabilize the transition state.
