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Contact-dependent growth inhibition systems in Acinetobacter
Eliana De Gregorio1,2, Raffaele Zarrilli3, Pier Paolo Di Nocera4
1Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università Federico II, Via Sergio Pansini 5, Naples, 80131, Italy.
Scientific Reports
|January 19, 2019
Summary
Researchers identified over 40 bacterial contact-dependent growth inhibition (CDI) systems in Acinetobacter. These systems were classified into two types, Type-I and Type-II, based on protein size and structural features.
Area of Science:
- Microbiology
- Bacterial Genetics
- Protein Structure
Background:
- Bacterial contact-dependent growth inhibition (CDI) systems mediate inter-bacterial interactions.
- CDI systems involve CdiA proteins exported by CdiB proteins, delivering toxins to target cells.
- Self bacteria possess CdiI antitoxins, while non-self bacteria are susceptible to CdiA-mediated growth inhibition.
Purpose of the Study:
- To identify and classify different CDI systems within pathogenic Acinetobacter genomes.
- To characterize the structural and genetic distinctions between identified CDI system types.
Main Methods:
- In silico genomic surveys of pathogenic Acinetobacter species.
- Comparative analysis of CdiA protein sequences, sizes, and domain structures.
- Investigation of gene organization and potential sequence exchange mechanisms.
Main Results:
- Over 40 distinct CDI systems were identified and categorized into Type-I and Type-II.
- Type-II CdiA proteins are large with repeat arrays, while Type-I CdiAs are smaller with variable HET regions.
- Significant differences were observed in CdiA-CT and pretoxin modules, as well as gene organization between Type-I and Type-II systems.
Conclusions:
- Two distinct types of CDI systems, Type-I and Type-II, are prevalent in pathogenic Acinetobacter.
- Structural and genetic variations suggest different evolutionary trajectories and functional adaptations of these CDI systems.
- The distribution of Type-I and Type-II systems varies across Acinetobacter species, indicating potential species-specific roles.
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