Del Prete Sonia, Vullo Daniela, De Luca Viviana, Carginale Vincenzo, Osman Sameh M, AlOthman Zeid, Supuran Claudiu T, Capasso Clemente
Università degli Studi di Firenze, Dipartimento Di Chimica, Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy; Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, 80131, Napoli, Italy.
Università degli Studi di Firenze, Dipartimento Di Chimica, Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy.
Bioorg Med Chem Lett. 2016 Apr 15;26(8):1941-6. doi: 10.1016/j.bmcl.2016.03.014. Epub 2016 Mar 7.
Carbonic anhydrases (CA, EC 4.2.1.1) are ubiquitous metalloenzymes, which catalyze the conversion of carbon dioxide (CO2) to bicarbonate (HCO3(-)) and protons (H(+)). In prokaryotes, the existence of genes encoding for α-, β- and γ-classes suggests that these enzymes play an important role in the prokaryotic physiology. It has been demonstrated, in fact, that their inhibition in vivo leads to growth impairment or growth defects of the microorganism. Ultimately, we started to investigate the biochemical properties and the inhibitory profiles of the α- and β-CAs identified in the genome of Vibrio cholerae, which is the causative agent of cholera. The genome of this pathogen encodes for CAs belonging to α, β and γ classes. Here, we report a sulfonamide inhibition study of the γ-CA (named VchCAγ) comparing it with data obtained for the α- and β-CA enzymes. VchCAγ activity (kcat=7.39 × 10(5)s(-1)) was significantly higher than the other γ-CAs. The inhibition study with a panel of sulfonamides and one sulfamate led to the detection of a large number of nanomolar VchCAγ inhibitors, including simple aromatic/heterocyclic sulfonamides (compounds 2-9, 11, 13-15, 24) as well as EZA, DZA, BRZ, BZA, TPM, ZNS, SLP, IND (KIs in the range of 66.2-95.3 nM). As it was proven that bicarbonate is a virulence factor of this bacterium and since ethoxzolamide was shown to inhibit this virulence in vivo, we propose that VchCA, VchCAβ and VchCAγ may be a target for antibiotic development, exploiting a mechanism of action rarely considered up until now, i.e., interference with bicarbonate supply as a virulence factor.
碳酸酐酶（CA，EC 4.2.1.1）是普遍存在的金属酶，可催化二氧化碳（CO₂）转化为碳酸氢根（HCO₃⁻）和质子（H⁺）。在原核生物中，编码α、β和γ类碳酸酐酶的基因的存在表明这些酶在原核生物生理学中发挥着重要作用。事实上，已经证明它们在体内的抑制会导致微生物的生长受损或生长缺陷。最终，我们开始研究在霍乱弧菌基因组中鉴定出的α-和β-碳酸酐酶的生化特性和抑制谱，霍乱弧菌是霍乱的病原体。该病原体的基因组编码属于α、β和γ类的碳酸酐酶。在此，我们报告了γ-碳酸酐酶（命名为VchCAγ）的磺胺抑制研究，并将其与α-和β-碳酸酐酶获得的数据进行比较。VchCAγ的活性（kcat = 7.39×10⁵ s⁻¹）明显高于其他γ-碳酸酐酶。用一组磺胺和一种氨基磺酸盐进行的抑制研究导致检测到大量纳摩尔级的VchCAγ抑制剂，包括简单的芳香族/杂环磺胺（化合物2 - 9、11、13 - 15、24）以及EZA、DZA、BRZ、BZA、TPM、ZNS、SLP、IND（抑制常数在66.2 - 95.3 nM范围内）。由于已证明碳酸氢根是这种细菌的一种毒力因子，并且由于乙氧唑胺在体内显示出抑制这种毒力，我们提出VchCA、VchCAβ和VchCAγ可能是抗生素开发的靶点，利用一种迄今为止很少被考虑的作用机制，即干扰作为毒力因子的碳酸氢根供应。
