Rationale:

The purpose of today’s lab was to continue researching our independent project topics to gather more information of the mechanisms behind phage holin and endolysin proteins.

Tools:

• PUBMED
• HHMI
• TMHMM

Procedure:

• Began by discussing previously discovered information and narrowing down a project title and worked on the QTM.
• Searched for articles discussing the peptidoglycan bridges in bacterial cell walls to find any information that suggests Arthrobacter has the same bridges as Staph. aureus.
• Discussed possible holin mechanisms given the presence of acidic residues placed outside the membrane.

Results:

• Noted a sequence of amino acids “PEPEK” that lies outside of the bacterial membrane called the periplasmic loop for the holin protein.
• No significant research could justify that Arthrobacter cell walls contain bridges similar to Staph. aureus.
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Conclusions:

It can be hypothesized that this region of amino acids is a key characteristic of phage holin and could possibly be used to determine function to phages with unknown holin genes. It is still unclear as to what mechanism stops the proton motive force, and very well could be caused by just the physical damage the holin protein inflicts on the bacterial plasma membrane.

Next Steps:

The next steps for this experiment is to finalize any research information on holins and endolysins and begin folding these proteins to determine any key characteristics that could help determine gene function in other phages.