Analysis of metal-binding features of the wild type and two domain-truncated mutant variants of Littorina littorea metallothionein reveals its cd-specific character
Palacios Bonilla, Òscar (Universitat Autònoma de Barcelona. Departament de Química)
Jiménez Martí, Elena (Universitat de Barcelona. Departament de Genètica)
Niederwanger, Michael (University of Innsbruck. Institute of Zoology and Center of Molecular Biosciences)
Gil-Moreno, Selene (Universitat Autònoma de Barcelona. Departament de Química)
Zerbe, Oliver (University of Zurich. Institute of Organic Chemistry)
Atrian i Ventura, Sílvia (Universitat de Barcelona. Departament de Genètica)
Dallinger, Reinhard (University of Innsbruck. Institute of Zoology and Center of Molecular Biosciences)
Capdevila Vidal, Mercè (Universitat Autònoma de Barcelona. Departament de Química)

Data:	2017
Resum:	After the resolution of the 3D structure of the Cd9-aggregate of the Littorina littorea metallothionein (MT), we report here a detailed analysis of the metal binding capabilities of the wild type MT, LlwtMT, and of two truncated mutants lacking either the N-terminal domain, Lltr2MT, or both the N-terminal domain, plus four extra flanking residues (SSVF), Lltr1MT. The recombinant synthesis and in vitro studies of these three proteins revealed that LlwtMT forms unique M9-LlwtMT complexes with Zn(II) and Cd(II), while yielding a complex mixture of heteronuclear Zn,Cu-LlwtMT species with Cu(I). As expected, the truncated mutants gave rise to unique M6-LltrMT complexes and Zn,Cu-LltrMT mixtures of lower stoichiometry with respect to LlwtMT, with the SSVF fragment having an influence on their metal binding performance. Our results also revealed a major specificity, and therefore a better metal-coordinating performance of the three proteins for Cd(II) than for Zn(II), although the analysis of the Zn(II)/Cd(II) displacement reaction clearly demonstrates a lack of any type of cooperativity in Cd(II) binding. Contrarily, the analysis of their Cu(I) binding abilities revealed that every LlMT domain is prone to build Cu4-aggregates, the whole MT working by modules analogously to, as previously described, certain fungal MTs, like those of C. neoformans and T. mesenterica. It is concluded that the Littorina littorea MT is a Cd-specific protein that (beyond its extended binding capacity through an additional Cd-binding domain) confers to Littorina littorea a particular adaptive advantage in its changeable marine habitat.
Ajuts:	Ministerio de Economía y Competitividad BIO2015-67358-C2-1-P Ministerio de Economía y Competitividad BIO2015-67358-C2-2-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-423
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Littorina littorea ; Metallothionein ; Metal binding ; Tridominial MT
Publicat a:	International journal of molecular sciences, Vol. 18 Núm. 7 (july 2017) , p. 1452, ISSN 1422-0067

DOI: 10.3390/ijms18071452
PMID: 28684668

16 p, 2.3 MB

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