OXA-type beta-lactamases.
OXA-type beta-lactamases.
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OXA 型 β-内酰胺酶。
DOI：
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发表时间：
1999
影响因子：
3.1
通讯作者：
P. Nordmann
中科院分区：
文献类型：
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作者：
T. Naas;P. Nordmann
OXA型（苯唑西林水解）酶分布广泛，主要在肠杆菌科和铜绿假单胞菌中描述。它们通常赋予对氨基青霉素和脲基青霉素的抗性，并对氯唑西林、苯唑西林和甲氧西林具有高水平的水解活性。克拉维酸对它们的活性有微弱的抑制作用，而氯化钠（NaCl）则有较强的抑制作用。苯唑西林水解性β-内酰胺酶属于Ambler D类，因此具有A类和C类β-内酰胺酶的活性丝氨酸位点。D类和A类或C类b-内酰胺酶之间的总体氨基酸同一性约为16%。到目前为止，已经通过序列和/或生物化学分析表征了24种Ambler D类酶，命名为OXA-1至OXA-22、AmpS和LCR-1，但是它们中没有一种的三维结构是可用的。虽然一些苯唑西林酶存在显著程度的氨基酸同一性（例如，OXA-1和OXA-4; OXA-10（PSE-2）衍生物; OXA-2和OXA-3），但它们中的大多数仅弱相关（20%至30%氨基酸同一性）。苯唑西林酶通常表现为限制谱表型。然而，最近观察到它们的谱向氧亚氨基头孢菌素和/或亚胺培南的扩展主要是由于OXA-2或OXA-10衍生物中的点突变。它们频繁的质粒和/或整合子定位为它们提供了广泛扩散的手段。
The OXA-type (oxacillin-hydrolysing) enzymes are widespread and have been mostly described in Enterobacteriaceae and in P. aeruginosa. They usually confer resistance to amino- and ureidopenicillin and possess high-level hydrolytic activity against cloxacillin, oxacillin, and methicillin. Their activities are weakly inhibited by clavulanic acid but sodium chloride (NaCl) possesses a strong inhibition activity. Oxacillin-hydrolysing b-lactamases belong to Ambler class D and thus possess an active serine site as classes A and C b-lactamases. Overall amino-acid identities between class D and class A or class C b-lactamases is about 16%. Until now, 24 Ambler class D enzymes, named OXA-1 to OXA-22, AmpS and LCR-1, have been characterised, either by sequence and/or by biochemical analyses, but for none of them a three dimensional structure is yet available. While some oxacillinases present a significant degree of amino-acid identity (for example, OXA-1 and OXA-4; OXA-10 (PSE-2) derivatives; OXA-2 and OXA-3), most of them are only weakly related (20% to 30% amino-acid identity). Oxacillinases usually display a restricted-spectrum phenotype. However extension of their spectrum towards oxyimino cephalosporins and/or imipenem has recently been observed mostly as a consequence of point mutations in OXA-2 or OXA-10 derivatives. Their frequent plasmid- and/or integron-location provide them a mean for a wide diffusion.