Molecular dynamics study of the metallochaperone Hah1 in its apo and Cu(I)‐loaded states: Role of the conserved residue M10

Poger, David; Fuchs, Jean-François; Nedev, Hristo; Ferrand, Michel; Crouzy, Serge

doi:10.1016/j.febslet.2005.08.052

Cited by 21 publications

(29 citation statements)

References 19 publications

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“…However, the small Ala10 side chain allows for fewer contacts than WT, extending to only Leu35 and Lys38, explaining the increased backbone dynamics in this region. We note that greater structural changes in apo versus holo forms because of the absence of Met10 was earlier reported for an Atox1 Met10Ser mutant on the basis of 5 ns MD simulations (25).…”

Section: Resultsmentioning

confidence: 72%

Differential Roles of Met10, Thr11, and Lys60 in Structural Dynamics of Human Copper Chaperone Atox1

Rodriguez-Granillo

Wittung-Stafshede

2009

Biochemistry

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Atox1 is a human copper (Cu) chaperone with the ferredoxin-like fold that binds Cu(I) via two Cys residues in a M(10)X(11)C(12)X(13)X(14)C(15) motif located in a solvent-exposed loop. Here, we report molecular dynamics simulations that reveal the roles of Met10, Thr11, and Lys60 in Atox1 structural dynamics. Whereas Met10 is conserved in all Atox1 homologues, Thr11 and Lys60 are exchanged for Ser and Tyr in bacteria. From simulations on apo and Cu(I) forms of Met10Ala, Thr11Ala, Lys60Ala, Thr11Ser, and Lys60Tyr variants, we have compared a range of structural and dynamic parameters such as backbone/Cu-loop dynamics, Cys solvent exposure, Cys-Cys distances, and cross-correlated motions. Surprisingly, Atox1 becomes more rigid in the absence of either Thr11 or Lys60, suggesting that these residues introduce protein flexibility. Lys60 and Thr11 also participate in electrostatic networks that stabilize the Cu-bound form and, in the apo form, determine the solvent exposure of the two Cys residues. In contrast, Met10 is buried in the hydrophobic core of Atox1, and its removal results in a dynamic protein structure. Prokaryotic residues are not good substitutes for the eukaryotic counterparts implying early divergence of Cu chaperone homologues. It appears that Atox1 residues have been conserved to ensure backbone/loop flexibility, electrostatic Cu site stabilization, and proper core packing. The discovered built-in flexibility may be directly linked to structural changes needed to form transient Atox1-Cu-target complexes in vivo.

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Section: Resultsmentioning

confidence: 72%

Differential Roles of Met10, Thr11, and Lys60 in Structural Dynamics of Human Copper Chaperone Atox1

Rodriguez-Granillo

Wittung-Stafshede

2009

Biochemistry

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“…The best 30 structures of the DYANA family were then subjected to restrained energy minimization with AMBER 8.0 (39). The force-field parameters for the metal ions were adapted from similar systems (40,41). The statistical analysis of the restrained energy minimization family of apoHSco1, Cu(I)HSco1, and Ni(II)HSco1 structures are reported, respectively, in Tables 5, 6, and 7, which are published as supporting information on the PNAS web site.…”

Section: Methodsmentioning

confidence: 99%

A hint for the function of human Sco1 from different structures

Banci

Bertini

Calderone

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

101

162

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The solution structures of apo, Cu(I), and Ni(II) human Sco1 have been determined. The protein passes from an open and conformationally mobile state to a closed and rigid conformation upon metal binding as shown by electrospray ionization MS and NMR data. The metal ligands of Cu(l) are two Cys residues of the CPXXCP motif and a His residue. The latter is suitably located to coordinate the metal anchored by the two Cys residues. The coordination sphere of Ni(II) in solution is completed by another ligand, possibly Asp. Crystals of the Ni(II) derivative were also obtained with the Ni(II) ion bound to the same His residue and to the two oxidized Cys residues of the CPXXCP motif. We propose that the various structures solved here represent the various states of the protein in its functional cycle and that the metal can be bound to the oxidized protein at a certain stage. Although it now seems reasonable that Sco1, which is characterized by a thioredoxin fold, has evolved to bind a metal atom via the di-Cys motif to act as a copper chaperone, the oxidized form of the nickel-bound protein suggests that it may also maintain the thioredoxin function

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“…However, the exact cause of this enhancement in both rate and extent of transfer varies between the two mutants. Previous molecular dynamics (MD) simulations of Met 10 Ser Atox1 indicated that Met-10 is essential for protein rigidity and for positioning the cysteines in proper orientation for Cu uptake (22). Greater flexibility may help to explain the almost 10-fold greater rate of Atox1 dissociation from the Met 10 Ala Atox1-Cu-BCA complex (k 2 ) compared to wild-type protein.…”

Section: Discussionmentioning

confidence: 99%

“…Although the methionine in the first position of the MXCXXC motif is conserved in all organisms, it is not directly involved in metal ligation (13). Instead, it has been proposed to act as a tether that modulates copper-binding loop structure (13,22).…”

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confidence: 99%