1.B.75 The DUF481 Putative Beta Barrel Porin (DUF481) Family The DUF481 family consists of large numbers of proteins from a wide range of Gram-negative bacteria. These proteins are of about 230 - 260 aas, but some are longer due to hydrophilic extensions. These proteins have an N-terminal signal sequence as well as 10 - 12 putative TM β-strands. An E. coli K12 member of the family is YdiY. These proteins probably belong to the: Outer Membrane Pore-forming Protein I (OMPP-I) Superfamily, but this suggestion has not been rigorously substantiated.
References:
Stancik, L.M., D.M. Stancik, B. Schmidt, D.M. Barnhart, Y.N. Yoncheva, and J.L. Slonczewski. (2002). pH-dependent expression of periplasmic proteins and amino acid catabolism in Escherichia coli. J. Bacteriol. 184: 4246-4258.
Examples:
TC#	Name	Organismal Type	Example
1.B.75.1.1	DUF481 outer membrane protein of 241 aas, an N-terminal signal sequence and 10 putative β-TMSs.	Proteobacteria	DUF481 OMP of Salmonella enterica

1.B.75.1.2	DUF481 outer membrane protein of 358 aas, an N-terminal signal sequence and 12 putative β-TMSs.	Planctomycetes	DUF481 OMP of Rhodopirellula sallentina

1.B.75.1.3	*YdiY OMP of 252 aas. Acid induces its synthesis (Stancik et al.* 2002).**	Proteobacteria	YdiY of E. coli K12

1.B.75.1.4	DUF481 outer membrane protein of 234 aas, an N-terminal signal sequence and 12 putative β-TMSs.	Proteobacteria	OMP of Arcobacter butzleri

1.B.75.1.5	DUF481 outer membrane protein of 240 aas, an N-terminal signal sequence and 12 putative β-TMSs.	Aquificae	OMP of Persephenella marina

1.B.75.1.6	DUF481 outer membrane protein of 247 aas, an N-terminal signal sequence and 11 putative β-TMSs.	Proteobacteria	OMP of Hirschia baltica

1.B.75.1.7	Putative outer membrane protein of 330 aas and 12 putative beta strands.	Proteobacteria	Putative porin of Myxococcus xanthus

Examples:
TC#	Name	Organismal Type	Example
1.B.75.2.1	DUF481 outer membrane protein of 276 aas, an N-terminal signal sequence and 12 putative β-TMSs.	Bacteroidetes	OMP of Saprospira grandis

1.B.75.2.2	DUF481 outer membrane protein of 259 aas, an N-terminal signal sequence and 11 putative β-TMSs.	Proteobacteria	OMP of Myxococcus fulvus

Examples:
TC#	Name	Organismal Type	Example
1.B.75.3.1	DUF481 outer membrane protein of 310 aas, an N-terminal signal sequence and 12 putative β-TMSs.	Cyanobacteria	*OMP of Synecococcus* sp.**

1.B.75.3.2	Salt-induced DUF481 outer membrane protein of 296 aas with an N-terminal signal sequence and 12 putative β-TMSs.	Cyanobacteria	OMP of Prochlorococcus marinus