The domain within your query sequence starts at position 880 and ends at position 926; the E-value for the TY domain shown below is 1.51e-4.



Thyroglobulin type I repeats.
SMART accession number:SM00211
Description: The N-terminal region of human thyroglobulin contains 11 type-1 repeats TY repeats are proposed to be inhibitors of cysteine proteases and binding partners of heparin.
Interpro abstract (IPR000716):

Thyroglobulin (Tg) is a large glycoprotein specific to the thyroid gland and is the precursor of the iodinated thyroid hormones thyroxine (T4) and triiodothyronine (T3). The N-terminal section of Tg contains 10 repeats of a domain of about 65 amino acids which is known as the Tg type-1 repeat [ (PUBMED:3595599) (PUBMED:8797845) ]. Such a domain has also been found as a single or repeated sequence in the HLA class II associated invariant chain [ (PUBMED:3038530) ]; human pancreatic carcinoma marker proteins GA733-1 and GA733-2 [ (PUBMED:2333300) ]; nidogen (entactin), a sulphated glycoprotein which is widely distributed in basement membranes and that is tightly associated with laminin; insulin-like growth factor binding proteins (IGFBP) [ (PUBMED:1709161) ]; saxiphilin, a transferrin-like protein from Rana catesbeiana (Bull frog) that binds specifically to the neurotoxin saxitoxin [ (PUBMED:8146142) ]; chum salmon egg cysteine proteinase inhibitor, and equistatin, a thiol-protease inhibitor from Actinia equina (sea anemone) [ (PUBMED:9153250) ]. The existence of Thyr-1 domains in such a wide variety of proteins raises questions about their activity and function, and their interactions with neighbouring domains. The Thyr-1 and related domains belong to MEROPS proteinase inhibitor family I31, clan IX.

Equistatin from A. equina is composed of three Thyr-1 domains; as with other proteins that contains Thyr-1 domains, the thyropins, they bind reversibly and tightly to cysteine proteases (inhibitor family C1). In equistatin inhibition of papain is a function of domain-1. Unusually domain-2 inhibits cathepsin D, an aspartic protease (inhibitor family A1) and has no activity against papain. Domain-3, does not inhibit either papain or cathepsin D, and its function or its target peptidase has yet to be determined [ (PUBMED:9153250) (PUBMED:12650938) ].

Family alignment:
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There are 14817 TY domains in 7575 proteins in SMART's nrdb database.

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