Structural modeling of Gene 32 protein and SSB's roles in DNA replication, recombination and repair

Students participating in the Students Modeling a Research Topic (SMART) team partnership program involving Lackey High School, University of Maryland Baltimore County and Milwaukee School of Engineering used 3‐D printing technology to create a physical model of T4 bacteriophage gene 32 protein and researched its role in denaturation and renaturation of DNA. Gene 32 protein is a single‐stranded binding protein (SSB) that has three domains: the core domain with an OB fold provides a structural trough for binding single stranded DNA (ssDNA); the B domain (amino acids 1–21) is responsible for cooperatively interacting with the core domains of other SSBs; and the A domain (C‐terminal 48 amino acids) binds to other proteins of the replication machinery and acts as a gate keeper by mimicking DNA thus controlling DNA binding. Gene 32 protein binds weakly to double stranded DNA (dsDNA). It is theorized that a region on the protein surface rich in lysine residues electrostatically interacts with the phosphates in the dsDNA major groove. dsDNA interaction might provide a means by which the protein could rapidly one‐dimensionally diffuse to transient single stranded regions on the DNA, thus facilitating its roles in DNA replication, recombination and repair. Supported by a grant from HHMI.