ID   HMD_METTL               Reviewed;         353 AA.
AC   Q50759;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   25-MAY-2022, entry version 104.
DE   RecName: Full=5,10-methenyltetrahydromethanopterin hydrogenase;
DE            EC=1.12.98.2;
DE   AltName: Full=H(2)-dependent methylene-H(4)MPT dehydrogenase;
DE   AltName: Full=H(2)-forming N(5),N(10)-methylenetetrahydromethanopterin dehydrogenase;
DE   AltName: Full=N(5),N(10)-methenyltetrahydromethanopterin hydrogenase;
GN   Name=hmd;
OS   Methanothermococcus thermolithotrophicus (Methanococcus
OS   thermolithotrophicus).
OC   Archaea; Euryarchaeota; Methanomada group; Methanococci; Methanococcales;
OC   Methanococcaceae; Methanothermococcus.
OX   NCBI_TaxID=2186;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 1-31; 141-151;
RP   210-225; 242-260; 274-293 AND 313-334, MASS SPECTROMETRY, FUNCTION,
RP   CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, AND SUBUNIT.
RC   STRAIN=ATCC 35097 / DSM 2095 / JCM 10549 / OCM 138 / SN-1;
RX   PubMed=8599536; DOI=10.1007/bf01692860;
RA   Hartmann G.C., Klein A.R., Linder M., Thauer R.K.;
RT   "Purification, properties and primary structure of H2-forming N5,N10-
RT   methylenetetrahydromethanopterin dehydrogenase from Methanococcus
RT   thermolithotrophicus.";
RL   Arch. Microbiol. 165:187-193(1996).
CC   -!- FUNCTION: Catalyzes the reversible reduction of methenyl-H(4)MPT(+) to
CC       methylene-H(4)MPT. {ECO:0000269|PubMed:8599536}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=5,10-methenyl-5,6,7,8-tetrahydromethanopterin + H2 = 5,10-
CC         methylenetetrahydromethanopterin + H(+); Xref=Rhea:RHEA:20017,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:18276, ChEBI:CHEBI:57818,
CC         ChEBI:CHEBI:58337; EC=1.12.98.2;
CC         Evidence={ECO:0000269|PubMed:8599536};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Temperature dependence:
CC         Optimum temperature is 80 degrees Celsius.
CC         {ECO:0000269|PubMed:8599536};
CC   -!- PATHWAY: One-carbon metabolism; methanogenesis from CO(2); 5,10-
CC       methylene-5,6,7,8-tetrahydromethanopterin from 5,10-methenyl-5,6,7,8-
CC       tetrahydromethanopterin (hydrogen route): step 1/1.
CC   -!- SUBUNIT: Homotetramer. {ECO:0000305|PubMed:8599536}.
CC   -!- MASS SPECTROMETRY: Mass=38039; Mass_error=38; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:8599536};
CC   -!- SIMILARITY: Belongs to the HMD family. {ECO:0000305}.
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DR   EMBL; X92848; CAA63433.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q50759; -.
DR   SMR; Q50759; -.
DR   UniPathway; UPA00640; UER00696.
DR   GO; GO:0047068; F:N5,N10-methenyltetrahydromethanopterin hydrogenase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0019386; P:methanogenesis, from carbon dioxide; IEA:UniProtKB-UniPathway.
DR   GO; GO:0006730; P:one-carbon metabolic process; IEA:UniProtKB-UniRule.
DR   Gene3D; 1.20.120.1300; -; 1.
DR   HAMAP; MF_01090; HMD; 1.
DR   InterPro; IPR008927; 6-PGluconate_DH-like_C_sf.
DR   InterPro; IPR010062; HMD.
DR   InterPro; IPR004889; HMD_C.
DR   InterPro; IPR038182; HMD_C_sf.
DR   InterPro; IPR024190; METHMP_Hmd.
DR   InterPro; IPR036291; NAD(P)-bd_dom_sf.
DR   Pfam; PF03201; HMD; 1.
DR   PIRSF; PIRSF016158; HMD; 1.
DR   PIRSF; PIRSF500165; HMDI; 1.
DR   SUPFAM; SSF48179; SSF48179; 1.
DR   SUPFAM; SSF51735; SSF51735; 1.
DR   TIGRFAMs; TIGR01723; hmd_TIGR; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Methanogenesis; One-carbon metabolism;
KW   Oxidoreductase.
FT   CHAIN           1..353
FT                   /note="5,10-methenyltetrahydromethanopterin hydrogenase"
FT                   /id="PRO_0000218514"
FT   CONFLICT        24
FT                   /note="R -> A (in Ref. 1; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        250
FT                   /note="C -> E (in Ref. 1; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        280
FT                   /note="D -> DAD (in Ref. 1; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        287
FT                   /note="D -> R (in Ref. 1; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        322
FT                   /note="C -> E (in Ref. 1; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   353 AA;  37988 MW;  C8C2FCB57E7242B4 CRC64;
     MKVAILGAGC YRTHAACGIT NFARAAEVAK KVGIPEITMT HSTITMGAEL LHLVDEIDEV
     VVSDPCFAEE PGLVIIDEFD PKEVMEAHLA GEPEKVMPAI RDAVKAKAKE VPKPPKGCIH
     FVHPEKVGLK VTSDDVEAVK DADIIITWLP KGGSQPAIIK KFVDAIKEGA IVTHACTIPT
     PKFAKIFKDL GRDDLNIISY HPGAVPEMKG QVFISEGYAS EEAVEKMYCI AKEARGTAYK
     MPANLISPVC DMGSAVTAPV YAAVLAYRDA VTKILGAPAD FAQMMADEAI TQILELMRKE
     GINNMEKTLD PKALTGTADS MCFGPLSDIL PPALKVLEKH AAEEESCCCE LKK