Molecular insights and functional analysis of isocitrate dehydrogenase in two gram-negative pathogenic bacteria

• Published in: World journal of microbiology & biotechnology 2024-11, Vol.40 (11), p.357-357, Article 357
• Main Authors: Xiong, Wei, Su, Rui, Han, Xueyang, Zhu, Mengxiao, Tang, Hongyiru, Huang, Shiping, Wang, Peng, Zhu, Guoping
• Format: Article
• Language: English
• Subjects: Acid resistance; Amino acids; Applied Microbiology; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biochemical characteristics; biochemical pathways; Biochemistry; Biomedical and Life Sciences; Biotechnology; Bronchopulmonary infection; Catalytic activity; Dehydrogenase; Dehydrogenases; Environmental Engineering/Biotechnology; Enzyme Stability; Functional analysis; Gram-negative bacteria; Heat inactivation; hospitals; Hydrogen-Ion Concentration; Inactivation; Isocitrate dehydrogenase; Isocitrate Dehydrogenase - chemistry; Isocitrate Dehydrogenase - genetics; Isocitrate Dehydrogenase - metabolism; Kinetics; Klebsiella; Klebsiella pneumoniae; Klebsiella pneumoniae - enzymology; Klebsiella pneumoniae - genetics; Legionella pneumophila; Legionella pneumophila - enzymology; Legionella pneumophila - genetics; Legionnaires' disease bacterium; Life Sciences; lungs; Magnesium; Manganese ions; Metabolic pathways; Microbiology; Molecular Weight; Multidrug resistance; multiple drug resistance; NAD - metabolism; NADP - metabolism; Oxidation resistance; pH effects; Substrate Specificity; Temperature; therapeutics
• ISSN: 0959-3993; 1573-0972; 1573-0972
• DOI: 10.1007/s11274-024-04169-7

Klebsiella pneumoniae and Legionella pneumophila are common Gram-negative bacteria that can cause lung infections. The multidrug resistance of K. pneumoniae presents a significant challenge for treatment. This study focuses on isocitrate dehydrogenase (IDH), a key enzyme in the oxidative metabolic pathway of these two bacteria. KpIDH and LpIDH were successfully overexpressed and purified, and their biochemical characteristics were thoroughly investigated. The study revealed that KpIDH and LpIDH are homodimeric enzymes with molecular weights of approximately 70 kDa. They are completely dependent on the coenzyme NADP + and are inactive towards NAD + . KpIDH exhibits the highest catalytic activity at pH 8.0 in the presence of Mn 2+ and at pH 7.8 in the presence of Mg 2+ . Its optimal catalytic performance is achieved with both ions at 55 °C. LpIDH exhibited its highest activity at pH 7.8 in the presence of Mn 2+ and Mg 2+ , respectively, and exhibits optimal catalytic performance at 45 °C. Heat inactivation studies showed that KpIDH and LpIDH retained over 80% of their activity after being exposed to 45 °C for 20 min. Furthermore, we successfully altered the coenzyme specificity of KpIDH and LpIDH from NADP + to NAD + by replacing four key amino acid residues. This study provides a comprehensive biochemical characterization of two multidrug-resistant bacterial IDHs commonly found in hospital environments. It enhances our understanding of the characteristics of pathogenic bacteria and serves as a reference for developing new therapeutic strategies.