Iodine accumulation in sea urchin larvae is dependent on peroxide

Miller, Ashley E. M.; Heyland, Andreas

doi:10.1242/jeb.077958

Cited by 25 publications

(26 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…32,33 The role of the aromatic component of I-Tyr in the absence of its zwitterion was therefore interrogated with hhIYD as well. Using the same fluoresence assay, I-Tyr was found to bind hhIYD with a ~90-fold weaker affinity than human IYD (Figure 1, Table 1).…”

Section: Resultsmentioning

confidence: 99%

Active Site Binding Is Not Sufficient for Reductive Deiodination by Iodotyrosine Deiodinase

et al. 2017

View full text Add to dashboard Cite

The minimal requirements for substrate recognition and turnover by iodotyrosine deiodinase were examined to learn the basis for its catalytic specificity. This enzyme is crucial for iodide homeostasis and the generation of thyroid hormone in chordates. 2-Iodophenol binds only very weakly to the human enzyme and is dehalogenated with a kcat/Km that is more than 4-orders of magnitude lower than that for iodotyrosine. This discrimination likely protects against a futile cycle of iodinating and deiodinating precursors of thyroid hormone biosynthesis. Surprisingly, a very similar catalytic selectivity was expressed by a bacterial homolog from Haliscomenobacter hydrossis. In this example, discrimination was not based on affinity since 4-cyano-2-iodophenol bound to the bacterial deiodinase with a Kd lower than that of iodotyrosine and yet was not detectably deiodinated. Other phenols including 2-iodophenol were deiodinated but only very inefficiently. Crystal structures of the bacterial enzyme with and without bound iodotyrosine are nearly superimposable and quite similar to the corresponding structures of the human enzyme. Likewise, the bacterial enzyme is activated for single electron transfer after binding to the substrate analog fluorotyrosine as previously observed with the human enzyme. A co-crystal structure of bacterial deiodinase and 2-iodophenol indicates that this ligand stacks on the active site FMN in a orientation analogous to that of bound iodotyrosine. However, 2-iodophenol association is not sufficient to activate the FMN chemistry required for catalysis, and thus the bacterial enzyme appears to share a similar specificity for halotyrosines even though their physiological roles are likely very different from those in humans.

show abstract

Section: Resultsmentioning

confidence: 99%

Active Site Binding Is Not Sufficient for Reductive Deiodination by Iodotyrosine Deiodinase

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The oxidative process is named peroxide-dependent diffusion (PDD) and occurs in macroalgae, bacteria, and animals outside of the chordates (Miller and Heyland, 2013). The resulting HIO may (i) diffuse into the cytoplasm to be accumulated, (ii) react to form volatile organoiodine compounds, or (iii) react in the apoplast with I − to produce I 2 , which can also migrate to the cytoplasm and be stored or volatilized (McFiggans et al, 2004; Leblanc et al, 2006).…”

Section: Iodine Dynamicsmentioning

confidence: 99%

Use of Iodine to Biofortify and Promote Growth and Stress Tolerance in Crops

et al. 2016

View full text Add to dashboard Cite

Iodine is not considered essential for land plants; however, in some aquatic plants, iodine plays a critical role in antioxidant metabolism. In humans, iodine is essential for the metabolism of the thyroid and for the development of cognitive abilities, and it is associated with lower risks of developing certain types of cancer. Therefore, great efforts are made to ensure the proper intake of iodine to the population, for example, the iodization of table salt. In the same way, as an alternative, the use of different iodine fertilization techniques to biofortify crops is considered an adequate iodine supply method. Hence, biofortification with iodine is an active area of research, with highly relevant results. The agricultural application of iodine to enhance growth, environmental adaptation, and stress tolerance in plants has not been well explored, although it may lead to the increased use of this element in agricultural practice and thus contribute to the biofortification of crops. This review systematically presents the results published on the application of iodine in agriculture, considering different environmental conditions and farming systems in various species and varying concentrations of the element, its chemical forms, and its application method. Some studies report beneficial effects of iodine, including better growth, and changes in the tolerance to stress and antioxidant capacity, while other studies report that the applications of iodine cause no response or even have adverse effects. We suggested different assumptions that attempt to explain these conflicting results, considering the possible interaction of iodine with other trace elements, as well as the different physicochemical and biogeochemical conditions that give rise to the distinct availability and the volatilization of the element.

show abstract

“…A NIS-independent mechanism for I 2 uptake has also been demonstrated in sea urchin larvae and seaweeds (7,35), suggesting that this mechanism could be widespread in nature. The functional relevance of iodine for the prostate gland is still unknown, but data from our group have shown antigrowth effects in models of prostatic diseases (25,36).…”

Section: Discussionmentioning

confidence: 89%