The domain within your query sequence starts at position 4 and ends at position 259; the E-value for the T4_deiodinase domain shown below is 1.6e-119.

LSVDLLITLQILPVFFSNCLFLALYDSVILLKHVALLLSRSKSTRGEWRRMLTSEGLRCV
WNSFLLDAYKQVKLGEDAPNSSVVHVSNPESGNNYASEKTADGAECHLLDFASAERPLVV
NFGSATUPPFTRQLPAFRQLVEEFSSVADFLLVYIDEAHPSDGWAVPGDSSLSFEVKKHR
NQEDRCAAAHQLLERFSLPPQCQVVADRMDNNANVAYGVAFERVCIVQRRKIAYLGGKGP
FSYNLQEVRSWLEKNF

T4_deiodinase

T4_deiodinase
PFAM accession number:PF00837
Interpro abstract (IPR000643):

Iodothyronine deiodinase ( EC 1.97.1.10 ) (DI) [ (PUBMED:7592917) ] is the vertebrate enzyme responsible for the deiodination of the prohormone thyroxine (T4 or 3,5,3',5'-tetraiodothyronine) into the biologically active hormone T3 (3,5,3'-triiodothyronine) and of T3 into the inactive metabolite T2 (3,3'-diiodothyronine). All known DI are proteins of about 250 residues that contain a selenocysteine at their active site. Three types of DI are known, type I is commonly found in the liver and kidney [ (PUBMED:8187873) ], type II is essential for providing the brain with the appropriate levels of T3 during the critical period of development, and type III (also known as thyroxine 5-deiodinase) is essential for the regulation of thyroid hormone inactivation during embryological development.

GO process:oxidation-reduction process (GO:0055114)
GO function:thyroxine 5'-deiodinase activity (GO:0004800)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry T4_deiodinase