Structural highlights
Function[TUBE_LAMBD] Forms the phage's tail tube composed of 32 hexameric disks. When it encounters the appropriate initiation complex gpM and gpL, it assembles in hexameric rings that stack on top of each others. Multimerization ceases when the correct tail length is achieved through a mechanism dependent on tail terminator protein.[1] [2] Publication Abstract from PubMedThe long flexible tail tube of bacteriophage lambda connects its capsid to the tail tip. Upon infection, a DNA ejection signal is passed from the tip, along the tube to the capsid that triggers passage of the DNA down the tube and into the host bacterium. The tail tube is built from repeating units of the major tail protein, gpV, which has two distinctive domains. Its N-terminal domain has the same fold as proteins that form the rigid inner tubes of contractile tail phages such as T4 and its C-terminal domain adopt an Ig-like fold of unknown function. We determined structures of the lambda tail tube in free tails and in virions before and after DNA ejection using cryo-electron microscopy. Modeling of the density maps reveals how electrostatic interactions and a mobile loop participate in assembly and also impart flexibility to the tube while maintaining its integrity. We also demonstrate how a common protein fold produces rigid tubes in some phages but flexible tubes in others. Mobile loops and electrostatic interactions maintainthe flexible tail tube of bacteriophage lambda.,Campbell PL, Duda RL, Nassur J, Conway JF, Huet A J Mol Biol. 2019 Nov 8. pii: S0022-2836(19)30647-3. doi:, 10.1016/j.jmb.2019.10.031. PMID:31711962[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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