1tlm

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spinqualitylabelsall models 1tlm, resolution 1.9Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURAL ASPECTS OF INOTROPIC BIPYRIDINE BINDING: CRYSTAL STRUCTURE DETERMINATION TO 1.9 ANGSTROMS OF THE HUMAN SERUM TRANSTHYRETIN-MILRINONE COMPLEX

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

The crystal structure of human transthyretin (TTR) complexed with, milrinone (2-methyl-5-cyano-3,4'-bipyridin-6(1H)-one), a positive, inotropic cardiac agent, has been refined to R = 17.4% for 8-1.9-A, resolution data. This report provides the first detailed description of, protein interactions for an inotropic bipyridine agent which is an, effective thyroid hormone binding competitor to transthyretin. Milrinone, is bound along the 2-fold axis in the binding site with its substituted, pyridone ring located deep within the channel of the two identical binding, domains of the TTR tetramer. In this orientation the 5-cyano group, occupies the same site as the 3'-iodine in the TTR complex with, 3,3'-diiodothyronine (Wojtczak, A., Luft, J., and Cody, V. (1992) J. Biol., Chem. 267, 353-357), which is 3.5 A deeper in the channel than thyroxine, (Blake, C. C. F., and Oately, S. J., (1977) Nature 268, 115-120). These, structural results confirm computer modeling studies of milrinone, structural homology with thyroxine and its TTR binding interactions and, explain the effectiveness of milrinone competition for thyroxine binding, to TTR. To understand the weaker binding affinity of the parent inotropic, drug, amrinone (5-amino-3,4'-bipyridin-6(1H)-one), modeling studies of its, TTR binding were carried out which indicate that the 5-amino group cannot, participate in strong interactions with TTR and the lack of the 2-methyl, further weakens amrinone binding.

Disease

Known diseases associated with this structure: Amyloid neuropathy, familial, several allelic types OMIM:[176300], Amyloidosis, senile systemic OMIM:[176300], Carpal tunnel syndrome, familial OMIM:[176300], Dystransthyretinemic hyperthyroxinemia OMIM:[176300]

About this Structure

1TLM is a Single protein structure of sequence from Homo sapiens with MIL as ligand. Full crystallographic information is available from OCA.

Reference

Structural aspects of inotropic bipyridine binding. Crystal structure determination to 1.9 A of the human serum transthyretin-milrinone complex., Wojtczak A, Luft JR, Cody V, J Biol Chem. 1993 Mar 25;268(9):6202-6. PMID:8454595

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