Earthworm Lumbricus rubellus MT-2: Metal Binding and Protein Folding of a True Cadmium-MT

نویسندگان

  • Gregory R. Kowald
  • Stephen R. Stürzenbaum
  • Claudia A. Blindauer
  • Reinhard Dallinger
چکیده

Earthworms express, as most animals, metallothioneins (MTs)-small, cysteine-rich proteins that bind d(10) metal ions (Zn(II), Cd(II), or Cu(I)) in clusters. Three MT homologues are known for Lumbricus rubellus, the common red earthworm, one of which, wMT-2, is strongly induced by exposure of worms to cadmium. This study concerns composition, metal binding affinity and metal-dependent protein folding of wMT-2 expressed recombinantly and purified in the presence of Cd(II) and Zn(II). Crucially, whilst a single Cd₇wMT-2 species was isolated from wMT-2-expressing E. coli cultures supplemented with Cd(II), expressions in the presence of Zn(II) yielded mixtures. The average affinities of wMT-2 determined for either Cd(II) or Zn(II) are both within normal ranges for MTs; hence, differential behaviour cannot be explained on the basis of overall affinity. Therefore, the protein folding properties of Cd- and Zn-wMT-2 were compared by ¹H NMR spectroscopy. This comparison revealed that the protein fold is better defined in the presence of cadmium than in the presence of zinc. These differences in folding and dynamics may be at the root of the differential behaviour of the cadmium- and zinc-bound protein in vitro, and may ultimately also help in distinguishing zinc and cadmium in the earthworm in vivo.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Metallothionein Induction in the Coelomic Fluid of the Earthworm Lumbricus terrestris following Heavy Metal Exposure: A Short Report

Earthworms are useful bioindicator organisms for soil biomonitoring. Recently the use of pollution biomarkers in earthworms has been increasingly investigated for soil monitoring and assessment. Earthworm coelomic fluid is particularly interesting from a toxicological perspective, because it is responsible for pollutant disposition and tissue distribution to the whole organism. The aim of the p...

متن کامل

Regulatory Plasticity of Earthworm wMT-2 Gene Expression

Metallothioneins (MTs) are multifunctional proteins occurring throughout the animal kingdom. While the expression and transcriptional regulation of MTs is well-studied in vertebrates, the mechanism of MT activation is still unknown for most invertebrates. Therefore, we examined wMT-2 gene regulation and expression patterns in Lumbricus rubellus and L. terrestris. Transcription levels, the occup...

متن کامل

Low levels of Cd induce persisting epigenetic modifications and acclimation mechanisms in the earthworm Lumbricus terrestris

Toxic effects of cadmium (Cd), a common soil pollutant, are still not very well understood, particularly in regard to its epigenetic impact. Therefore, the aim of this study was to assess DNA methylation changes and their persistence in the earthworm Lumbricus terrestris upon chronic low dose Cd exposure using methylation sensitive amplification polymorphism (MSAP). Moreover, the biomarker resp...

متن کامل

Evaluation of DNA damage and lipoperoxidation content in red earthworm, Lumbricus rubellus exposed to zinc oxide nanoparticles

Manufactured nanoparticles have a wide range of application due to their advantageous properties whencompared with their bulk forms. There is a growing concern regarding the safety of nanoparticles. This studyaimed to evaluate the cell membrane lipoperoxidation (LPO) and DNA integrity in red earthworm Lumbricusrubellus when exposed to artificial soil systems containing different concentration o...

متن کامل

Toxicokinetics of metals in the earthworm Lumbricus rubellus exposed to natural polluted soils--relevance of laboratory tests to the field situation.

The aim of this study was to estimate the bioavailability of essential (Zn, Cu) and non-essential metals (Cd, Pb) to the earthworm Lumbricus rubellus exposed to soils originating from a gradient of metal pollution in Southern Poland. Metal uptake and elimination kinetics were determined and related to soils properties. Experimental results were compared with tissue metal concentrations observed...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 17  شماره 

صفحات  -

تاریخ انتشار 2016