>TIGR00143 hypF [NiFe] hydrogenase maturation protein HypF; InterPro: IPR004421 The large subunit of [NiFe]-hydrogenase, as well as other nickel metalloenzymes, is synthesized as a precursor devoid of the metalloenzyme active site. This precursor then undergoes a complex post-translational maturation process that requires a number of accessory proteins , , . Members of the HypF family are accessory proteins involved in hydrogenase maturation. They contain the following domains: acylphosphatase, zinc fingers (2 repeats), a YrdC-like domain, and a C-terminal domain with a putative O-carbamoyltransferase motif. The presence of CO and CN- ligands of the active site iron atoms is essential for [NiFe]-hydrogenase enzyme activity . Both ligands have been suggested to originate from carbamoylphosphate , which is required for maturation of [NiFe]-hydrogenases . Escherichia coli HypF interacts with carbamoylphosphate as a substrate and releases inorganic phosphate . In addition, HypF also cleaves ATP into AMP and pyrophosphate in the presence of carbamoylphosphate. This, and the fact that HypF catalyzes a carbamoylphosphate-dependent pyrophosphate ATP exchange reaction, suggest that the protein catalyzes the activation of carbamoylphosphate . The mechanism of action of HypF, as well as of its individual domains, is not yet clear. Mutations in any of the three major signature motifs, the acylphosphatase, the zinc fingers, and the O-carbamoyltransferase motif, can block carbamoylphosphate phosphatase activity. This indicates an integrated cooperativity between these domains in the cleavage reaction . The N-terminal acylphosphatase (ACP) domain is thought to support the conversion of carbamoylphosphate into CO and CN- , . Biochemical results demonstrating its ACP activity are not available , . ACPs are small enzymes that specifically catalyze the hydrolysis of carboxylphosphate bonds in acylphosphates, including carbamoylphosphate . Zinc fingers have been implicated in bivalent cation binding or as part of a chaperone domain interacting with the large subunit precursor, but experimental studies on such a function are lacking thus far. The YrdC-like domain is present in protein families with regulatory functions (IPR012200 from INTERPRO, IPR010923 from INTERPRO) and has been implicated in RNA binding . It is not clear what function it may have in members of the HypF family. A C-terminal domain is distantly related to peptidase M22, but contains a conserved O-carbamoyltransferase motif required for the carbamoylphosphate phosphatase activity . The function of this domain is not clear. Nomenclature note: the following names are used as synonyms of HypF: HupY in Azotobacter chroococcum, HupN in Rhizobium leguminosarum, HydA in Escherichia coli. In other organisms, these names are used to designate various "hydrogenase cluster" proteins unrelated to the members of this family. ; GO: 0030528 transcription regulator activity.

Probab=91.03  E-value=0.27  Score=27.54  Aligned_cols=71  Identities=20%  Similarity=0.122  Sum_probs=41.7

Q ss_pred             HHCCC-CCCCCCCC---C---C--------CCCEECHHHHHHCCCC-------CCCCCCCCCCCCCCCCCCHHHHCCCCC
Q ss_conf             85787-47103751---5---6--------5770288899508676-------786201244465334760898516784
Q gi|254780310|r   18 CIYPS-ICPIYSRI---I---N--------LRFCLCGHCWSKIHFI-------TATEHILKNNKDNIDKDPLKSMQKDLP   75 (119)
Q Consensus        18 ~lfP~-~C~~C~~~---~---~--------~~~~lC~~C~~~l~~i-------~~~~C~~Cg~~~~~~~~C~~C~~~~~~   75 (119)
T Consensus       120 Y~YPF~~CT~CGPRfTi~~aLPYDRe~T~m~~FpLC~~C~~EY~dP~DRRFHAQ~~aCP~CGP~L~f~~-----------  188 (799)
T TIGR00143       120 YLYPFISCTDCGPRFTIIEALPYDRENTSMADFPLCPDCEKEYKDPLDRRFHAQAIACPRCGPKLEFVS-----------  188 (799)
T ss_pred             CCCCCCCCCCCCCCHHHHHCCCCCCCCCCCCCCCCCHHHHHHCCCCCCCEEEECCCCCCCCCCCCCEEC-----------
T ss_conf             127432435567525676427888874334578988468997078876304644627733578653021-----------


Q ss_pred             HHHHHHHHCCCHHHHHHHHHHHHCC
Q ss_conf             3530120002127999999974478
Q gi|254780310|r   76 LTQIRSVTLYCDMSCVLVRLLKYHD  100 (119)
Q Consensus        76 f~~~~a~~~Y~~~~r~lI~~~Ky~~  100 (119)
T Consensus       189 -~~~~vIae~~~al~~a~~~L~~G~  212 (799)
T TIGR00143       189 -RGGEVIAEKDDALKEAAKLLKKGK  212 (799)
T ss_pred             -CCCEEEECCCHHHHHHHHHHCCCC
T ss_conf             -687167527736899999840797