This domain is found in a wide variety of contexts, but mostly occurring in cell wall associated proteins. A lack of conserved catalytic residues suggests that it is a binding domain. From context, possible substrates are hyaluronate or fibronectin (personal obs: C Yeats). This is further evidenced by [1]. Possibly the exact substrate is N-acetyl glucosamine. Finding it in the same protein as Pfam:PF05089 further supports this proposal. It is found in the C-terminal part of Swiss:O82833, which is removed during maturation ([2]). Some of the proteins it is found in (e.g. Swiss:Q9RL69) are involved in methicillin resistance ([3]). The name FIVAR derives from Found In Various Architectures.

1: Identification of a fibronectin-binding protein from Staphylococcus epidermidis. Williams RJ, Henderson B, Sharp LJ, Nair SP; Infect Immun 2002;70:6805-6810. PMID:12438356

2: Posttranslational processing of polysaccharide lyase: maturation route for gellan lyase in Bacillus sp. GL1. Miyake O, Kobayashi E, Nankai H, Hashimoto W, Mikami B, Murata K; Arch Biochem Biophys 2004;422:211-220. PMID:14759609

3: Tn551-mediated insertional inactivation of the fmtB gene encoding a cell wall-associated protein abolishes methicillin resistance in Staphylococcus aureus. Komatsuzawa H, Ohta K, Sugai M, Fujiwara T, Glanzmann P, Berger-BachiB, Suginaka H; J Antimicrob Chemother 2000;45:421-431. PMID:10896508