This work presents a computational analysis of the molecular characteristics shared by the adenylation domains from traditional nonribosomal peptide synthetases (NRPSs) and the group of the freestanding homologous enzymes: alpha-aminoadipate semialdehyde dehydrogenase, alpha-aminoadipate reductase and the protein Ebony. The results of systematic sequence comparisons allow us to conclude that a specificity-conferring code, similar to that described for the NRPSs, can be recognized in such enzymes. The structural and functional roles of the residues involved in the substrate selection and binding are proposed through the analysis of the predicted interactions of the model active sites and their respective substrates. The indications deriving from this study can be useful for the programming of experiments aimed at a better characterization and at the engineering of this emerging group of single NRPS modules that are responsible for amino acid selection, activation and modification in the absence of other NRPS assembly line components.
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http://dx.doi.org/10.1111/j.1742-4658.2004.04522.x | DOI Listing |
ACS Chem Biol
January 2025
Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan.
Developing novel nonribosomal peptides (NRPs) requires a comprehensive understanding of the enzymes involved in their biosynthesis, particularly the substrate amino acid recognition mechanisms in the adenylation (A) domain. This study focused on the A domain responsible for adenylating l-2,4-diaminobutyric acid (l-Dab) within the synthetase of polymyxin, an NRP produced by NBRC3020. To date, investigations into recombinant proteins that selectively adenylate l-Dab─exploring substrate specificity and enzymatic activity parameters─have been limited to reports on A domains found in enzymes synthesizing l-Dab homopolymers (pldA from USE31 and pddA from NBRC15115), which remain exceedingly rare.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Biochemistry, University of Zurich, Winterthurerstrass 190, 8057 Zurich, Switzerland.
Type III clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) systems (type III CRISPR-Cas systems) use guide RNAs to recognize RNA transcripts of foreign genetic elements, which triggers the generation of cyclic oligoadenylate (cOA) second messengers by the Cas10 subunit of the type III effector complex. In turn, cOAs bind and activate ancillary effector proteins to reinforce the host immune response. Type III systems utilize distinct cOAs, including cyclic tri- (cA3), tetra- (cA4) and hexa-adenylates (cA6).
View Article and Find Full Text PDFFEBS J
January 2025
Department of Biological Sciences, Chungnam National University, Daejeon, Korea.
Previous studies have identified three families of knotted phytochrome photoreceptors in cyanobacteria. We describe a fourth type: 'hybrid' phytochromes with putative bilin-binding cysteine residues in both their N-terminal 'knot' extensions and cGMP-phosphodiesterase/adenylate cyclase/FhlA (GAF) domains, which we designate as dual-cysteine bacteriophytochromes (DCBs). Recombinant expression of DCBs in Escherichia coli yields photoactive phycocyanobilin (PCB) adducts with red/far-red photocycles similar to those of the GAF-Cys-containing cyanobacterial phytochromes (Cph1s).
View Article and Find Full Text PDFNat Struct Mol Biol
January 2025
Key Laboratory of Multiple Organ Failure (Ministry of Education), Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Fatty acids (FAs) are essential building blocks for all the domains of life, of which bacterial de novo synthesis, called type II FA synthesis (FAS II), is energetically expensive. The recycling of exogenous FAs (eFAs) partially relieves the FAS II demand and, therefore, compromises the efficacy of FAS II-directed antimicrobials. The versatile acyl-acyl carrier protein (ACP) synthetase, AasS, enables bacterial channeling of diverse eFA nutrients through holo-ACP, an activated form of ACP.
View Article and Find Full Text PDFFront Microbiol
December 2024
Scientific Research Institute of Systems Biology and Medicine, Moscow, Russia.
Introduction: WhiA is a conserved protein found in numerous bacteria. It consists of an HTH DNA-binding domain linked with a homing endonuclease (HEN) domain. WhiA is one of the most conserved transcription factors in reduced bacteria of the class Mollicutes.
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