Here, we describe the structure of three actinobacteriophage capsids that infect Mycobacterium smegmatis. The capsid structures were resolved to approximately six angstroms, which allowed confirmation that each bacteriophage uses the HK97-fold to form their capsid. One bacteriophage, Rosebush, may have a novel variation of the HK97-fold. Four novel accessory proteins that form the capsid head along with the major capsid protein were identified. Two of the accessory proteins were minor capsid proteins and showed some homology, based on bioinformatic analysis, to the TW1 bacteriophage. The remaining two accessory proteins are decoration proteins that are located on the outside of the capsid and do not resemble any previously described bacteriophage decoration protein. SDS-PAGE and mass spectrometry was used to identify the accessory proteins and bioinformatic analysis of the accessory proteins suggest they are used in many actinobacteriophage capsids.

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Enterovirus 71, or EV 71, is responsible for causing Hand, Foot, and Mouth disease in humans. In particular, it is especially deadly when children and small infants are exposed. The objective of this research paper is to address the possibility of a novel antiviral drug that can be used once infection of EV 71 has occurred. The methods for this research include transformation of E. coli with the genetic information from Enterovirus 71, growth of the E. coli colonies in the lab setting, 2C protein purification, and ATPase assays with drug testing. Of the 364 drugs tested in the ATPase assay, a combination of two of them (Mitrofudil and N6- Benzyladenosine) indicated a stoppage in activity of ATPase, signaling no further activity of the enzyme and viral proliferation.

Mycobacterium tuberculosis and abscessus are major human pathogens that are part of the Actinobacteria phylum. Increasing multiple drug resistance in these bacteria has led to a renewed interest in using viruses that infect these bacteria for therapy. In order to understand these viruses, a course-based undergraduate research experience (CURE) program run by SEA-PHAGES at the University of Pittsburgh and HHMI has isolated, sequenced, and annotated over 3000 actinobacteriophages (viruses that infect Actinobacteria). Little work has been done to investigate the structural diversity of these phage, all of which are thought to use a common protein fold, the HK97-fold, in their major capsid protein. Here we describe the structure of three actinobacteriophage capsids isolated by students that infect Mycobacterium smegmatis. The capsid structures were resolved to approximately 6 angstroms, which allowed confirmation that each phage uses the HK97-fold to form their capsid. One phage, Rosebush, has a novel variation of the HK97-fold. Four novel accessory proteins, that form the capsid head along with the major capsid protein, were identified that show limited or no homology to known proteins. The genes that encode the proteins were identified using SDS-PAGE and mass spectrometry. Bioinformatic analysis of the accessory proteins suggest they are used in many actinobacteriophage capsids.