Publication Date:
1978-09-22
Description:
The molecular conformation of the halogen-free thyroxine analog 4-methoxy-3,5,3'-trimethyl-L-thyronine -n-acetyl ethyl ester has been determined by x-ray diffraction techniques. The unsubstituted parent compound, trimethylthyronine, has significant biological activity in rat thymocyte tests when compared with the thyroid hormone 3,5,3'-triiodo-L-thyronine (T3). Although no activity data are available for the analog studied, it is presumed to be inactive because of the 4-methoxy blocking group. The observed conformation of this structure is similar to that found for the natural hormone T(3). The 3'-methyl group is distal, the overall conformation is cisoid, and the diphenyl ether conformation is twist-skewed. The results of this diffraction study show that methyl substituents are capable of maintaining the thyronine conformation required for hormonal activity; they suggest that iodine enhances hormone-protein binding because of the electronic effects it produces either by alteration of molecular charge distributions or by direct charge-transfer interactions with the serum or nuclear binding proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cody, V -- New York, N.Y. -- Science. 1978 Sep 22;201(4361):1131-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/684433" target="_blank"〉PubMed〈/a〉
Keywords:
Models, Molecular
;
Molecular Conformation
;
Thyronines/*analogs & derivatives
;
X-Ray Diffraction
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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