title: How to hide zinc in a small protein.
abstract: Small cysteine-rich proteins (metallothioneins) and related domains of some large proteins (e.g., lysine methyltransferases) bind tri- and tetranuclear zinc clusters with topologies resembling fragments of Zn(II) sulfide minerals. These clusters are ubiquitous in animals, plants, and bacteria. Bacterial metallothioneins can also contain histidines as cluster ligands and embed Zn(II) with a "treble-clef"-like finger fold. This unusual embedded Zn(II) is "hidden" and surprisingly inert toward Zn or Cd exchange. Clearly, proteins can exert fine control over both the thermodynamics and kinetics of zinc binding in thiolate clusters. Genome sequences suggest that related zinc-finger sites are common in a variety of bacteria.
authors.affiliation: School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Blindauer
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Sadler
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000737:chemistry / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D019281:Dimerization; D006639:Histidine / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D008239:Lysine / Q000737:chemistry / Q000378:metabolism; D008668:Metallothionein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism; D017967:Zinc Compounds / Q000737:chemistry / Q000378:metabolism; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D008024:Ligands; D011506:Proteins; D013438:Sulfhydryl Compounds; D013440:Sulfides; D017967:Zinc Compounds; D002104:Cadmium; D006639:Histidine; D008668:Metallothionein; D015032:Zinc; D008239:Lysine; D003545:Cysteine; C031238:zinc sulfide