This model describes a domain found in PilB, a protein important for pilin expression, N-terminal to a domain coextensive to with the known peptide methionine sulfoxide reductase (MsrA), a protein repair enzyme, of E. coli. Among the early completed genomes, this module is found if and only if MsrA is also found, whether N-terminal to MsrA (as for Helicobacter pylori), C-terminal (as for Treponema pallidum), or in a separate polypeptide. Although the function of this region is not clear, an auxiliary function to MsrA is suggested [Protein fate, Protein modification and repair, Cellular processes, Adaptations to atypical conditions]. Length = 134
Score = 91.2 bits (227), Expect = 2e-25
Identities = 45/124 (36%), Positives = 53/124 (42%), Gaps = 45/124 (36%)
Query: 14 KEELKKRLTPMQYHVTQEKGTER--------------Y--IGSNLLLLITN--------- 48
EE K L+P QY V + KGTE+ Y IG L +
Sbjct: 1 DEEWKAVLSPEQYRVLRNKGTEKPFTGEYDDHFEEGIYVCIGCGEPLFSSTTKFDSGCGW 60
Query: 49 ---------------PD----MVRTEVTCSKCDAHLGHVFNDGPA-PTRRRFCINSASVD 88
PD M RTEV C+ CD HLGHVF DGP P R+CINSAS+
Sbjct: 61 PSFFEPISGDAIKYTPDRSHGMRRTEVRCANCDGHLGHVFKDGPKEPGGLRYCINSASLK 120
Query: 89 FVPD 92
F+P
Sbjct: 121 FIPA 124
Methionine sulfoxide reduction is an important process, by which cells regulate biological processes and cope with oxidative stress. MsrA, a protein involved in the reduction of methionine sulfoxides in proteins, has been known for four decades and has been extensively characterized with respect to structure and function. However, recent studies revealed that MsrA is only specific for methionine-S-sulfoxides. Because oxidized methionines occur in a mixture of R and S isomers in vivo, it was unclear how stereo-specific MsrA could be responsible for the reduction of all protein methionine sulfoxides. It appears that a second methionine sulfoxide reductase, SelR, evolved that is specific for methionine-R-sulfoxides, the activity that is different but complementary to that of MsrA. Thus, these proteins, working together, could reduce both stereoisomers of methionine sulfoxide. This domain is found both in SelR proteins and fused with the peptide methionine sulfoxide reductase enzymatic domain pfam01625. The domain has two conserved cysteine and histidines. The domain binds both selenium and zinc. The final cysteine is found to be replaced by the rare amino acid selenocysteine in some members of the family. This family has methionine-R-sulfoxide reductase activity. Length = 124
This model describes a domain found in PilB, a protein important for pilin expression, N-terminal to a domain coextensive to with the known peptide methionine sulfoxide reductase (MsrA), a protein repair enzyme, of E. coli. Among the early completed genomes, this module is found if and only if MsrA is also found, whether N-terminal to MsrA (as for Helicobacter pylori), C-terminal (as for Treponema pallidum), or in a separate polypeptide. Although the function of this region is not clear, an auxiliary function to MsrA is suggested.
>PF01641 SelR: SelR domain; InterPro: IPR002579 Peptide methionine sulphoxide reductase (Msr) reverses the inactivation of many proteins due to the oxidation of critical methionine residues by reducing methionine sulphoxide, Met(O), to methionine []
It is present in most living organisms, and the cognate structural gene belongs to the so-called minimum gene set [, ]. The domains: MsrA and MsrB, reduce different epimeric forms of methionine sulphoxide. This group represents MsrB, the crystal structure of which has been determined to 1.8A []. The overall structure shows no resemblance to the structures of MsrA (IPR002569 from INTERPRO) from other organisms; though the active sites show approximate mirror symmetry. In each case, conserved amino acid motifs mediate the stereo-specific recognition and reduction of the substrate. Unlike the MsrA domain, the MsrB domain activates the cysteine or selenocysteine nucleophile through a unique Cys-Arg-Asp/Glu catalytic triad. The collapse of the reaction intermediate most likely results in the formation of a sulphenic or selenenic acid moiety. Regeneration of the active site occurs through a series of thiol-disulphide exchange steps involving another active site Cys residue and thioredoxin. In a number of pathogenic bacteria, including Neisseria gonorrhoeae, the MsrA and MsrB domains are fused; the MsrA being N-terminal to MsrB. This arrangement is reversed in Treponema pallidum. In N. gonorrhoeae and Neisseria meningitidis, a thioredoxin domain is fused to the N terminus. This may function to reduce the active sites of the downstream MsrA and MsrB domains. ; GO: 0008113 peptide-methionine-(S)-S-oxide reductase activity, 0055114 oxidation-reduction process; PDB: 1L1D_A 3E0O_D 2KZN_A 3HCG_B 3HCH_A 2L1U_A 3MAO_A 2K8D_A 3HCJ_A 3HCI_A ....
>PF03226 Yippee-Mis18: Yippee zinc-binding/DNA-binding /Mis18, centromere assembly; InterPro: IPR004910 This entry represents the Yippee-like (YPEL) family of putative zinc-binding proteins which is highly conserved among eukaryotes
The first protein in this family to be characterised, the Yippee protein from Drosophila, was identified by yeast interaction trap screen as a protein that physically interacts with moth hemolin []. It was subsequently found to be a member of a highly conserved family of proteins found in diverse eukaryotes including plants, animals and fungi []. Mammals contain five members of this family, YPEL1 to YPEL5, while other organisms tend to contain only two or three members. The mammalian proteins all appear to localise in the nucleus. YPEL1-4 are located in an unknown structure located on or close to the mitotic apparatus in the mitotic phase, whereas in the interphase they are located in the nuclei and nucleoli. In contrast, YPEL5 is localised to the centrosome and nucleus during interphase and at the mitotic spindle during mitosis, suggesting a function distinct from that of YPEL1-4. The localisation of the YPEL proteins suggests a novel, thopugh still unknown, function involved in cell division.
>pdb|2KV1|A Chain A, Insights Into Function, Catalytic Mechanism And Fold Evolution Of Mouse Selenoprotein Methionine Sulfoxide Reductase B1 Through Structural Analysis Length = 124
