>gi|91092534|ref|XP_967693.1| PREDICTED: similar to methionine-R-sulfoxide reductase [Tribolium castaneum] gi|270006619|gb|EFA03067.1| hypothetical protein TcasGA2_TC010923 [Tribolium castaneum]
Score = 129 bits (327), Expect = 2e-40
Identities = 44/81 (54%), Positives = 56/81 (69%)
Query: 14 KEELKKRLTPMQYHVTQEKGTERPFSGKYNKNTESGTYTCIVCAQPLFSSQTKFDSGCGW 73
EE K L+P QY V + KGTE+PF+G+Y+ + E G Y CI C +PLFSS TKFDSGCGW
Sbjct: 1 DEEWKAVLSPEQYRVLRNKGTEKPFTGEYDDHFEEGIYVCIGCGEPLFSSTTKFDSGCGW 60
Query: 74 PAFNDVLDQGKVKLTKDTSHG 94
P+F + + +K T D SHG
Sbjct: 61 PSFFEPISGDAIKYTPDRSHG 81
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
Score = 126 bits (318), Expect = 5e-39
Identities = 46/84 (54%), Positives = 57/84 (67%)
Query: 11 KINKEELKKRLTPMQYHVTQEKGTERPFSGKYNKNTESGTYTCIVCAQPLFSSQTKFDSG 70
K + EELKK+LTP+QY VTQ GTE PF+ +Y N E G Y I C +PLFSS+ KFDSG
Sbjct: 1 KPSDEELKKKLTPLQYEVTQNAGTEPPFTNEYWDNKEEGIYVDITCGEPLFSSEDKFDSG 60
Query: 71 CGWPAFNDVLDQGKVKLTKDTSHG 94
CGWP+F + + V +D SHG
Sbjct: 61 CGWPSFYKPISEEVVAYERDESHG 84
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
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 []
Probab=100.00 E-value=2.8e-52 Score=299.55 Aligned_cols=93 Identities=53% Similarity=0.921 Sum_probs=90.2
Q ss_pred HHHHHhcCCHHHHHHHhhcCCCCCCCCCCCCCCCCeEEEeccCCCccccCCCcccCCCCCcccccccCCCCeEEeecCCC
Q psy12346 14 KEELKKRLTPMQYHVTQEKGTERPFSGKYNKNTESGTYTCIVCAQPLFSSQTKFDSGCGWPAFNDVLDQGKVKLTKDTSH 93 (107)
Q Consensus 14 d~ewk~~Lt~~qy~V~r~~gTE~pfsg~y~~~~~~G~Y~C~~Cg~pLF~S~~KFdSg~GWPSF~~pi~~~~v~~~~D~s~ 93 (107)
|+|||++|||+||+|||++||||||||+|++++++|+|+|++||+|||+|++||+||||||||++||.+++|.++.|.++
T Consensus 1 d~ew~~~Lt~~qy~V~r~~gTE~pfsg~y~~~~~~G~Y~C~~Cg~pLF~S~~Kf~Sg~GWPSF~~~i~~~~v~~~~D~s~ 80 (124)
T PF01641_consen 1 DEEWRKRLTPEQYRVLREKGTERPFSGEYWDHKEEGIYVCAVCGTPLFSSDTKFDSGCGWPSFWQPIPGDAVKEREDFSH 80 (124)
T ss_dssp -HHHHHHSCHHHHHHHHHTTSSSTTSSGGCCTTSSEEEEETTTS-EEEEGGGEETSSSSSSEESSCSSTTSEEEEEEECT
T ss_pred CHHHHhhCCHHHHHHHHhcCCCCCCccCCcCCCCCEEEEcCCCCCccccCcccccCCcCCccccCcCChHHEEEeccccC
Confidence 78999999999999999999999999999999999999999999999999999999999999999999999999999999
Q ss_pred CceeeEEeCCCCC
Q psy12346 94 GKLYGDLVSSHPK 106 (107)
Q Consensus 94 gm~RtEV~C~~c~ 106 (107)
||+||||+|++|+
T Consensus 81 g~~R~Ev~C~~Cg 93 (124)
T PF01641_consen 81 GMVRTEVRCARCG 93 (124)
T ss_dssp SSEEEEEEETTTC
T ss_pred CceEEEEEecCCC
Confidence 9999999999997
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 ....
>PF09855 DUF2082: Nucleic-acid-binding protein containing Zn-ribbon domain (DUF2082); InterPro: IPR018652 This family of proteins contains various hypothetical prokaryotic proteins as well as some Zn-ribbon nucleic-acid-binding proteins
There has been an apparent duplication event in the Halobacteriaceae lineage (Haloarcula, Haloferax, Haloquadratum, Halobacterium and Natromonas). There appears to be a separate duplication in Methanosphaera stadtmanae.
