Functional diversity of YbbN/CnoX proteins: Insights from a comparative analysis of three thioredoxin-like oxidoreductases from Pseudomonas aeruginosa, , Xylella fastidiosa and Escherichia coli

Author(s)

Meireles, Diogo de Abreu ; Yokomizo, Cesar Henrique ; Silva, Francisnei Pedrosa ; Venancio, Thiago Motta ; Degenhardt, Maximilia Fraz o de Souza ; Oliveira, Cristiano Luis Pinto de ; Netto, Luis Eduardo Soares

• Document type: Journal article
• Source: REDOX BIOLOGY; v. 72, p. 15-pg., 2024-03-29.

Abstract

YbbN/CnoX are proteins that display a Thioredoxin (Trx) domain linked to a tetratricopeptide domain. YbbN from Escherichia coli (EcYbbN) Ec YbbN) displays a co-chaperone (holdase) activity that is induced by HOCl. Here, we compared Ec YbbN with YbbN proteins from Xylella fastidiosa (XfYbbN) Xf YbbN) and from Pseudomonas aeruginosa (PaYbbN). Pa YbbN). Ec YbbN presents a redox active Cys residue at Trx domain (Cys63), 24 residues away from SQHC motif (SQHC[N24]C) 24 ]C) that can form mixed disulfides with target proteins. In contrast, Xf YbbN and Pa YbbN present two Cys residues in the CXXC (CAPC) motif, while only Pa YbbN shows the Cys residue equivalent to Cys63 of Ec YbbN. Our phylogenetic analysis revealed that most of the YbbN proteins are in the bacteria domain of life and that their members can be divided into four groups according to the conserved Cys residues. Ec YbbN (SQHC[N24]C), 24 ]C), Xf YbbN (CAPC[N24]V) 24 ]V) and Pa YbbN (CAPC[N24]C) 24 ]C) are representatives of three sub-families. In contrast to Ec YbbN, both Xf YbbN and Pa YbbN: (1) reduced an artificial disulfide (DTNB) and (2) supported the peroxidase activity of Peroxiredoxin Q from X. fastidiosa, , suggesting that these proteins might function similarly to the canonical Trx enzymes. Indeed, Xf YbbN was reduced by Xf Trx reductase with a high catalytic efficiency (kcat/Km k cat /K m = 1.27 x 107 7 M- 1 s-- 1 ), similar to the canonical Xf Trx (XfTsnC). Xf TsnC). Furthermore, Ec YbbN and Xf YbbN, but not Pa YbbN displayed HOCl-induced holdase activity. Remarkably, Ec YbbN gained disulfide reductase activity while lost the HOCl-activated chaperone function, when the SQHC was replaced by CQHC. In contrast, the Xf YbbN CAPA mutant lost the disulfide reductase activity, while kept its HOCl-induced chaperone function. In all cases, the induction of the holdase activity was accompanied by YbbN oligomerization. Finally, we showed that deletion of ybbN gene did not render in P. aeruginosa more sensitive stressful treatments. Therefore, YbbN/CnoX proteins display distinct properties, depending on the presence of the three conserved Cys residues. (AU)

• FAPESP's process: 13/07937-8 - Redoxome - Redox Processes in Biomedicine
• Grantee: Ohara Augusto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 15/07271-5 - Functional and structural characterization of YbbN protein of Xylella fastidiosa
• Grantee: César Henrique Yokomizo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral