1.E.10 The Bacillus subtilis φ29 Holin (φ29 Holin) Family

Phage φ29 gene 14 encodes the late protein GP14 which is required for phage φ29-promoted host cell lysis. When expressed in E. coli, it leads to cell death without lysis. When expressed together with phage φ29 lysozyme or an unrelated murein-degrading enzyme, cell lysis is also observed. Thus, protein 14 is a nonspecific holin in the cytoplasmic membrane of B. subtilis. It is identical to the phage PZA lysis protein and nearly identical to the phage B103 lysis protein. It is 34% identical to the phage GA-1 holin.


This family belongs to the Holin IV Superfamily .
 

References:

Mondal, A. and A.B. Kolomeisky. (2025). Why Antiholins? Thermodynamic and Kinetic Arguments to Explain the Robustness of Bacteriophage Cell Lysis. J Phys Chem Lett 16: 2920-2926.
Shi, Y., Y. Yan, W. Ji, B. Du, X. Meng, H. Wang, and J. Sun. (2012). Characterization and determination of holin protein of Streptococcus suis bacteriophage SMP in heterologous host. Virol J 9: 70.
Steiner, M., W. Lubitz, and U. Bläsi. (1993). The missing link in phage lysis of gram-positive bacteria: gene 14 of Bacillus subtilis phage phi 29 encodes the functional homolog of lambda S protein. J. Bacteriol. 175: 1038-1042.
Tedin, K., A. Resch, M. Steiner, and U. Bläsi. (1995). Dual translational start motif evolutionarily conserved in the holin gene of Bacillus subtilis phage phi 29. Virology 206: 479-484.
Examples:

TC#NameOrganismal TypeExample
1.E.10.1.1

Lysis holin protein (late protein GP14) (Tedin et al. 1995).

Bacillus phage f29

GP14 (131 aas; spP11188)

 
1.E.10.1.2

Pneumococcal phage SV1 holin 1.

Firmicute viruses

Pneumococcal phage SV1 holin 1

 
1.E.10.1.3

Holin HolSMP (Orf43) (Shi et al. 2012).

Firmicute viruses

HolSMP of Streptococcus suis phage SMP

 
1.E.10.1.4

Anti-holin (gene 14) of 132 aas and 2 TMSs.  It determines the precise timing of host cell lysis.  Antiholins may also be stabilizing elements that ensure robust cell lysis under fluctuating physiological conditions (Mondal and Kolomeisky 2025).

Antiholin of Bacillus phage B103 (Bacteriophage B103)