1SB6

Solution structure of a cyanobacterial copper metallochaperone, ScAtx1

Summary for 1SB6

• Entry DOI: 10.2210/pdb1sb6/pdb
• NMR Information: BMRB: 6172
• Descriptor: copper chaperone ScAtx1 (1 entity in total)
• Functional Keywords: copper chaperone, new metal binding motif, structural proteomics in europe, spine, structural genomics, chaperone
• Biological source: Synechocystis sp.
• Total number of polymer chains: 1
• Total formula weight: 6690.51

Authors

Banci, L.,Bertini, I.,Ciofi-Baffoni, S.,Su, X.C.,Borrelly, G.P.,Robinson, N.J.,Structural Proteomics in Europe (SPINE) (deposition date: 2004-02-10, release date: 2004-04-27, Last modification date: 2024-05-01)

Primary citation

Banci, L.,Bertini, I.,Ciofi-Baffoni, S.,Su, X.C.,Borrelly, G.P.,Robinson, N.J.
Solution Structures of a Cyanobacterial Metallochaperone: INSIGHT INTO AN ATYPICAL COPPER-BINDING MOTIF.
J.Biol.Chem., 279:27502-27510, 2004

PubMed Abstract: The Atx1 copper metallochaperone from Synechocystis PCC 6803, ScAtx1, interacts with two P(1)-type copper ATPases to supply copper proteins within intracellular compartments, avoiding ATPases for other metals en route. Here we report NMR-derived solution structures for ScAtx1. The monomeric apo form has a betaalphabetabetaalpha fold with backbone motions largely restricted to loop 1 containing Cys-12 and Cys-15. The tumbling rate of Cu(I)ScAtx1 (0.1-0.8 mm) implies dimers. Experimental restraints are satisfied by symmetrical dimers with Cys-12 or His-61, but not Cys-15, invading the copper site of the opposing subunit. A full sequence of copper ligands from the cell surface to thylakoid compartments is proposed, considering in vitro homodimer liganding to mimic in vivo liganding in ScAtx1-ATPase heterodimers. A monomeric high resolution structure for Cu(I)ScAtx1, with Cys-12, Cys-15, and His-61 as ligands, is calculated without violations despite the rotational correlation time. (2)J(NH) couplings in the imidazole ring of His-61 establish coordination of N(epsilon2) to copper. His-61 is analogous to Lys-65 in eukaryotic metallochaperones, stabilizing Cu(I)S(2) complexes but by binding Cu(I) rather than compensating charge. Cys-Cys-His ligand sets are an emergent theme in some copper metallochaperones, although not in related Atx1, CopZ, or Hah1. Surface charge (Glu-13) close to the metal-binding site of ScAtx1 is likely to support interaction with complementary surfaces of copper-transporting ATPases (PacS-Arg-11 and CtaA-Lys-14) but to discourage interaction with zinc ATPase ZiaA and so inhibit aberrant formation of copper-ZiaA complexes.

PubMed: 15075318
DOI: 10.1074/jbc.M402005200

Experimental method

SOLUTION NMR