1.E.40 The Mycobacterial 4 TMS Phage Holin (MP4 Holin) Family A member of the Mycobacterial 4 TMS Phage Holin family was first identified by Catalao et. al (Catalão et al. 2012). This family includes several 4 TMS homologues, all of which are from phage, bacteria and archaea. None of these proteins is functionally characterized. These proteins have their 4 TMSs present in an apparent 2 + 2 TMS arrangement, and the two pairs of 2 TMSs may be duplicates of each other.
This family belongs to the Holin IV Superfamily .
References:
Catalao MJ., Gil F., Moniz-Pereira J., Sao-Jose C. and Pimentel M. (2013). Diversity in bacterial lysis systems: bacteriophages show the way. FEMS Microbiol Rev. 37(4):554-71.
Meng, L.H., F. Ke, Q.Y. Zhang, and Z. Zhao. (2022). Functional Analysis of the Endopeptidase and Holin From Cyanophage PaV-LD. Front Microbiol 13: 849492.
Palmer, M., B.P. Hedlund, S. Roux, P.K. Tsourkas, R.K. Doss, C. Stamereilers, A. Mehta, J.A. Dodsworth, M. Lodes, S. Monsma, T. Glavina Del Rio, T.W. Schoenfeld, E.A. Eloe-Fadrosh, and D.A. Mead. (2020). Diversity and Distribution of a Novel Genus of Hyperthermophilic Viruses Encoding a Proof-Reading Family-A DNA Polymerase. Front Microbiol 11: 583361.
Examples:
TC#	Name	Organismal Type	Example
1.E.40.1.1	The Gp37 4 TMS (221 aas) putative holin	Mycobacterial phage	Gp37 of mycobacterial phage PBI1

1.E.40.1.2	The Gp44 putative holin of 164 aas and 4 TMSs	Mycobacterial phage	Gp44 of mycobacterial phage Patience

1.E.40.1.3	Gp28 putative holin of 161 aas and 4 TMSs	Mycobacterial phage	Gp28 of mycobacterial phage Che9c

1.E.40.1.4	Gp29 putative holin of 160 aas and 4 TMSs	Mycobacterial phage	Gp29 of mycobacterial phage BigNuz

Examples:
TC#	Name	Organismal Type	Example
1.E.40.2.1	Putative holin of 121 aas and 4 TMSs	Cyanobacteria	*Putative holin of Fischerella* sp. JSC11**

1.E.40.2.2	Putative holin of 121 aas and 4 TMSs. The holin functions of a homolog of 54% identity to this holin have been well documented for cyanophage PaV-LD from the cyanobacterium, Planktothrix agardhii (Meng et al. 2022).	Cyanobacteria	Putative holin of Microcoleus vaginatus

1.E.40.2.3	Putative holin of 121 aas and 4 TMSs	Cyanobacteria	Putative holin of Anabaena variablis

Examples:
TC#	Name	Organismal Type	Example
1.E.40.3.1	Putative holin of 121 aas and 4 TMSs	β-Proteobacteria	Putative holin of Burkholderia rhizoxinica

1.E.40.3.2	Putative holin of 113 aas and 4 TMSs	β-Proteobacteria	Putative holin of Ralstonia solanacearum

1.E.40.3.3	Putative holin of 145 aas and 4 TMSs	Verucomicrobia	Putative holin of Opititus terrae

1.E.40.3.4	Putative holin of 120aas and 4 TMSs	Firmicutes	Putative holin of Amphibacillus xylanus

1.E.40.3.5	Putative holin of 128 aas and 4 TMSs	Firmicutes	Putative holin of Gemella morbillorum

1.E.40.3.6	Putative holin	Spirochaetes	Holin of Leptospira interrongans

1.E.40.3.7	Putative holin of 129 aas and 4 TMSs.		Holin of Candidatus Wolfebacteria bacterium

1.E.40.3.8	*Putative holin of 146 aas and 4 TMSs (Palmer et al.* 2020).**		Holin of Chloroflexi bacterium G233

Examples:
TC#	Name	Organismal Type	Example
1.E.40.4.1	Putative holin of 115 aas and 4 TMSs	Firmicutes	Putative holin of Ammonifex degensii

1.E.40.4.2	Putative holin of 117 aas and 4 TMSs	Firmicutes	Putative holin of Paeibucillus mucilagiosus

1.E.40.4.3	Putative holin with 122 aas and 4 TMSs. Shows limited sequence similiarity with 1.E.19.4.1.	Firmicutes	Putative holin of Clostridium perfringens

1.E.40.4.4	Uncharacterized protein of 161 aas and 4 TMSs.		UP of Pediococcus damnosus

Examples:
TC#	Name	Organismal Type	Example
1.E.40.5.1	Largely hydrophilic protein with an N-terminal putative 4 TMS holin domain (720 aas). The large hydrophilic domain may be a Type I phosphodiesterase/nucleotide pyrophosphatase.	Chloroflexi	Puative holin fusion protein of Caldilinia aeophila

1.E.40.5.2	Phage holin family proteinof 141 aas and 4 TMSs.		Holin of Methanobrevibacter arboriphilus

Examples:
TC#	Name	Organismal Type	Example
1.E.40.6.1	Holin of 139 aas and 4 TMSs.		Holin of Cellulosimicrobium cellulans (Arthrobacter luteus)