Authors:

Marielle Denise Melendez

Date Created:

Not specified

Course Title:

Professor:

Not specified

About Paper:

Transferable genetic elements, such as plasmids and bacteriophages, can pose a significant threat to bacterial colonies. As a result, bacteria evolved numerous defenses against invasive DNA. Pandemic Vibrio cholerae strains reportedly employ the DdmABC complex, a Lamassu-2 system, to defend against potential decimation. DdmABC is composed of three proteins: DdmA, DdmB, and DdmC. Based on hypothesized structures of the complex, DdmA & DdmC exhibit structural similarities with the domains of Acinetobacter baumannii's Cap4 protein's endonuclease and an SMC-like (Structural Maintenance of Chromosomes) protein, respectively. Given a protein's structure strongly correlates to its function, this information suggests that DdmC recognizes and binds to DNA, and DdmA cleaves the DNA indiscriminately. Based on this, we speculate that the DdmABC complex may trigger apoptosis upon recognition of palindromic DNA within the hairpin structure of foreign plasmids. More investigation is needed to understand the functions of each protein, the precise mechanism, and the triggers of self-induced cell death. Our research aims to confirm the activation of apoptosis by the DdmABC system. After generating a recombinant protein from protein purification, biochemical assays will be applied to assess the functionality of the protein complex, and cryogenic electron microscopy will be utilized to elucidate the complex's molecular structure. While the DdmABC complex is unique to V.cholerae, Lamassu systems like DdmABC are widespread in all bacteria. By studying the DdmABC complex, we hope to gain more structural and mechanistic information on intricate defense systems in bacteria.

Source:

Purdue University / 2023

Topics:

No topics listed

Co-authors:

Marielle Denise Melendez