Thermococcus onnurineus NA1 is an anaerobic archaeon usually found in a deep-sea hydrothermal vent area, which can use elemental sulfur (S⁰) as a terminal electron acceptor for energy. Sulfur, essential to many biomolecules such as sulfur-containing amino acids and cofactors including iron-sulfur cluster, is usually mobilized from cysteine by the pyridoxal 5′-phosphate- (PLP-) dependent enzyme of cysteine desulfurase (CDS). We determined the crystal structures of CDS from Thermococcus onnurineus NA1 (ToCDS), which include native internal aldimine (NAT), gem-diamine (GD) with alanine, internal aldimine structure with existing alanine (IAA), and internal aldimine with persulfide-bound Cys356 (PSF) structures. The catalytic intermediate structures showed the dihedral angle rotation of Schiff-base linkage relative to the PLP pyridine ring. The ToCDS structures were compared with bacterial CDS structures, which will help us to understand the role and catalytic mechanism of ToCDS in the archaeon Thermococcus onnurineus NA1.

中文翻译：

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来自古生热球菌NA1的半胱氨酸脱硫酶的催化中间晶体结构。

oncoriccus onnurineus NA1是一种厌氧古细菌，通常存在于深海热液喷口区域，可以使用元素硫（S ⁰）作为能量的末端电子受体。对于许多生物分子（例如含硫氨基酸和包括铁硫簇在内的辅助因子）必不可少的硫，通常通过半胱氨酸脱硫酶（CDS）的吡咯醛5'-磷酸-（PLP-）依赖性酶从半胱氨酸中动员。我们确定了Thermococcus onnurineus CDS的晶体结构NA1（ToCDS），包括天然内部醛亚胺（NAT），具有丙氨酸的gem-diamine（GD），具有现有丙氨酸的内部醛亚胺结构（IAA）和具有与硫化物结合的Cys356（PSF）结构的内部醛亚胺。催化中间结构显示席夫碱键相对于PLP吡啶环的二面角旋转。将ToCDS结构与细菌CDS结构进行了比较，这将有助于我们了解ToCDS在古生嗜热球菌NA1中的作用和催化机理。