title: The YHS-Domain of an Adenylyl Cyclase from Mycobacterium phlei Is a Probable Copper-Sensor Module.
abstract: YHS-domains are small protein modules which have been proposed to bind transition-metal ions like the related TRASH-domains. They are found in a variety of enzymes including copper-transporting ATPases and adenylyl cyclases. Here we investigate a class IIIc adenylyl cyclase from Mycobacterium phlei which contains a C-terminal YHS-domain linked to the catalytic domain by a peptide of 8 amino acids. We expressed the isolated catalytic domain and the full-length enzyme in E. coli. The catalytic domain requires millimolar Mn2+ as a cofactor for efficient production of cAMP, is unaffected by low micromolar concentrations of Cu2+ and inhibited by concentrations higher than 10 μM. The full-length enzyme also requires Mn2+ in the absence of an activator. However, 1-10 μM Cu2+ stimulate the M. phlei adenylyl cyclase sixfold when assayed with Mn2+. With Mg2+ as the probable physiological cofactor of the adenylyl cyclase Cu2+ specifically switches the enzyme from an inactive to an active state. Other transition-metal ions do not elicit activity with Mg2+. We favor the view that the YHS-domain of M. phlei adenylyl cyclase acts as a sensor for copper ions and signals elevated levels of the transition-metal via cAMP. By analogy to TRASH-domains binding of Cu2+ probably occurs via one conserved aspartate and three conserved cysteine-residues in the YHS-domain.
authors.affiliation: Department of Biochemistry, University of Bayreuth, Bayreuth, Germany.
authors.forename: Jürgen Ulrich
authors.initials: JU
authors.lastname: Linder
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D027682:Cation Transport Proteins / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D000073840:Copper-Transporting ATPases; D004789:Enzyme Activation; D015870:Gene Expression; D007700:Kinetics; D008969:Molecular Sequence Data; D009168:Mycobacterium phlei / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D016415:Sequence Alignment
chemical_list: D027682:Cation Transport Proteins; D003300:Copper; D000251:Adenosine Triphosphatases; D000262:Adenylyl Cyclases; D000073840:Copper-Transporting ATPases