A fp14 is involved in regulating the length of Anti‐feeding prophage ( A fp)

Summary The anti‐feeding prophage ( A fp), a phage‐tail‐like particle that causes cessation of feeding in the N ew Z ealand grass grub, C ostelytra zealandica , is encoded by 18 open reading frames ( afp1–18 ). C ‐terminal truncations of afp14 resulted in shortened A fp particles, suggesting that A fp14 is involved in A fp length determination. We constructed an A fp assembly system ( afp1–18 ), wherein A fp14 was truncated after the N ‐terminal 88 residues. This construct, when expressed in trans in E scherichia coli expressing a N ‐terminal 98‐amino acid A fp14 construct, yielded fully assembled A fp but no assembled A fp was detected in the case of a N ‐terminal 96‐amino acid A fp14 construct. These results suggested that the 98 N ‐terminal, amino acid residues of A fp14 is crucial for the initiation of A fp assembly via baseplate formation. Trans ‐based expression of wild‐type afp14 resulted in A fp particles of varying lengths, all of which were shorter than the wild‐type A fp particle. On the other hand, similar expression of A fp14 harboring a C ‐terminal extension ( KLLEH 6 ) resulted in elongated A fp particles. This information, combined with bioinformatics data, allowed us to propose a model delineating the mechanism and role of A fp14 in the maturation of the A fp particle.