9.B.52 The Outer Membrane Protein YaiO (YaiO) Family The YaiO integral membrand barrel protein of E. coli has been shown to be present in the outer membrane (Marani et al. 2006). All members of the family have an N-terminal transmembrane targetting TMS and 14, 13 or 12 putative TM β-strands. Although a few members of the family are annotated as acyl transferases, and others are annotated as outer membrane lipoproteins, most of them are annotated as YaiO family members. No published functional data establish the porin activity of YaiO, but homology with several established porins of the Outer Membrane Pore-forming Protein (OMPP) Superfamily I and its predicted topology has led to the conclusion that YaiO is a functional β-barrel porin. This family was formerly assigned TC# 9.B.52.
This family belongs to the Outer Membrane Pore-forming Protein I (OMPP-I) Superfamily .
References:
Shahein, M.A., A.N. Dapgh, E. Kamel, S.F. Ali, E.A. Khairy, H.A. Abuelhag, and A.S. Hakim. (2021). Advanced molecular characterization of enteropathogenic isolated from diarrheic camel neonates in Egypt. Vet World 14: 85-91.
Examples:
TC#	Name	Organismal Type	Example
1.B.95.1.1	The outer membrane protein, YaiO of 257 aas with 1 N-terminal α-TMS, and 14 predicted β-strands (Marani et al. 2006). This protein was identified in pathogenic E. coli strains that infect camels and was considered to be a housekeeping gene (Shahein et al. 2021).		YaiO of E. coli

1.B.95.1.2	YaiO family outer membrane beta-barrel protein of 261 aas and 1 N-terminal TM		*YaiO of Stenotrophomonas* sp. CC22-02**

1.B.95.1.3	YaiO family outer membrane beta-barrel protein of 260 aas and 1 N-terminal TM		YaiO of Pseudoxanthomonas suwonensis

Examples:
TC#	Name	Organismal Type	Example
1.B.95.2.1	Uncharacterized outer membrane protein of 258 aas with 1 N-terminal α-TMS, and 14 predicted β-strands.		UP of Hydrogenobacter thermophilus

1.B.95.2.2	Uncharacterized outer membrane protein of 260 aas with 1 N-terminal α-helix and 13 predicted β-strands.		UP of Polaromonas naphthalenivorans

1.B.95.2.3	Uncharacterized protein of 418 aas, 1 N-terminal α-TMS and 12 C-terminal β-strands.		UP of Burkholderia pseudomallei

Examples:
TC#	Name	Organismal Type	Example
1.B.95.3.1	YaiO family outer membrane beta-barrel protein of 266 aas and 1 N-terminal TMS.		YaiO of Halomonas subterranea

1.B.95.3.2	YaiO family outer membrane beta-barrel protein of 258 aas and 1 N-terminal TMS.		*YaiO of Polaromonas* sp.**

1.B.95.3.3	YaiO family outer membrane beta-barrel protein of 375 aas and 1 N-terminal TMS. This protein is similar in sequence to the protein with TC# 1.B.55.4.1, suggesting that this protein is a porin.		YaiO of Lysobacter soli

1.B.95.3.4	YaiO family outer membrane beta-barrel protein of 375 aas and 1 N-terminal TMS. This protein is similar in sequence to several proteins in family with TC# 1.B.55, and therefore is likely to be a porin.		YaiO of Pseudomonas xinjiangensis

1.B.95.3.5	YaiO family outer membrane beta-barrel protein of 267 aas and 1 N-terminal TM		YaiO of Solimonas fluminis

1.B.95.3.6	YaiO family outer membrane beta-barrel protein of 267 aas and 1 N-terminal TM		YaiO of Methylophilaceae bacterium

Examples:
TC#	Name	Organismal Type	Example
1.B.95.4.1	Uncharacterized protein of 242 aas and 1 N-terminal TMS		UP of Waddlia chondrophila

1.B.95.4.2	Uncharacterized protein of 233 aas and 1 N-terminal TM		UP of Candidatus Rubidus massiliensis

1.B.95.4.3	Outer membrane beta-barrel protein of 226 aas and 1 N-terminal TM		*OMP of Parachlamydia* sp. C2**

1.B.95.4.4	Uncharacterized protein of 245 aas and 1 or 2 N-terminal TMSs		UP of Acinetobacter haemolyticus

Examples:
TC#	Name	Organismal Type	Example
1.B.95.5.1	YaiO family outer membrane beta-barrel protein of 409 aas and 1 N-terminal TMS.		YaiO of Candidatus Atribacteria bacterium (marine sediment metagenome)

1.B.95.5.2	YaiO family outer membrane beta-barrel protein of 409 aas and 1 N-terminal TMS.		YaiO of Algoriphagus aquimarinus

1.B.95.5.3	YaiO family outer membrane beta-barrel protein of 400 aas and 1 N-terminal TM		*YaiO of Candidatus Sulfopaludibacter* sp. SbA6**