2XMU

Copper chaperone Atx1 from Synechocystis PCC6803 (Cu2 form)

Summary for 2XMU

• Entry DOI: 10.2210/pdb2xmu/pdb
• Related: 1SB6 2XMJ 2XMK 2XMM 2XMT 2XMV 2XMW
• Descriptor: SSR2857 PROTEIN, COPPER (I) ION (3 entities in total)
• Functional Keywords: chaperone, copper homeostasis, p-type atpases, metal transport, metallochaperone, cu(i)-binding, cu(i)-cluster, trafficking
• Biological source: SYNECHOCYSTIS SP. PCC 6803
• Total number of polymer chains: 2
• Total formula weight: 13635.21

Authors

Badarau, A.,Firbank, S.J.,McCarthy, A.A.,Banfield, M.J.,Dennison, C. (deposition date: 2010-07-29, release date: 2010-08-18, Last modification date: 2023-12-20)

Primary citation

Badarau, A.,Firbank, S.J.,Mccarthy, A.A.,Banfield, M.J.,Dennison, C.
Visualizing the Metal-Binding Versatility of Copper Trafficking Sites .
Biochemistry, 49:7798-, 2010

PubMed Abstract: Molecular systems have evolved to permit the safe delivery of copper. Despite extensive studies, many copper site structures involved in copper homeostasis, even for the well-studied metallochaperone Atx1, remain unresolved. Cyanobacteria import copper to their thylakoid compartments for use in photosynthesis and respiration and possess an Atx1 that we show can adopt multiple oligomeric states when metalated, capable of binding up to four copper ions. Two-copper- and four-copper-loaded dimers exist in solution at low micromolar concentrations, and head-to-head and side-to-side arrangements, respectively, can be crystallized, with the latter binding a [Cu(4){mu(2)-S(gamma)(Cys)}(4)Cl(2)](2-) cluster. The His61Tyr mutation on loop 5 weakens head-to-head dimerization, yet a side-to-side dimer binding a similar cluster as in the wild-type protein, but with phenolate coordination, is present. The cognate metal-binding domains (MBDs) of the P-type ATPases CtaA and PacS, which are proposed to donate copper to and accept copper from Atx1, respectively, are monomeric in the presence of copper. The structure of the MBD of Cu(I)-PacS shows a crystallographic trimer arrangement around a [Cu(3){mu(2)-S(gamma)(Cys)}(3){S(gamma)(Cys)}(3)](2-) cluster that is very similar to that found for an alternate form of the His61Tyr Atx1 mutant. Copper transfer from the MBD of CtaA to Atx1 is favorable, but delivery from Atx1 to the MBD of PacS is strongly dependent upon the dimeric form of Atx1. A copper-induced switch in Atx1 dimer structure may have a regulatory role with cluster formation helping to buffer copper.

PubMed: 20726513
DOI: 10.1021/BI101064W

Experimental method

X-RAY DIFFRACTION (1.75 Å)