PDZ domain 2 of harmonin isoforms a, b, and c, and related domains
PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 2 of harmonin isoforms a, b, and c, and related domains. Harmonin (also known as Usher Type 1C, PDZ-73 and AIE-75) is a key organizer of the Usher (USH) protein interactome. USH syndrome is the leading cause of hereditary sensory deaf-blindness in humans; three clinically distinct types of USH have been identified, type 1 to 3. The gene encoding harmonin (USH1C) is the causative gene for the USH type 1C phenotype. There are at least 10 alternatively spliced isoforms of harmonin, which are divided into three subclasses (a, b, and c). All isoforms contain the first two PDZ domains and the first coiled-coil domain. The a and b isoforms all have a third PDZ domain. The different PDZ domains are responsible for interactions with all known Usher syndrome type 1 proteins, and most Usher syndrome type 2 proteins. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This harmonin family PDZ2 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.
Feature 1:peptide binding site [polypeptide binding site]
Evidence:
Comment:based on canonical PDZ domains with structure
Comment:PDZ domains specifically recognize and bind to short C-terminal peptide motifs, but can also recognize internal peptide motifs and certain lipids
Structure:2KBS: PDZ domain 2 of human harmonin binds the C-terminal peptide of cadherin-23; contacts at 4A - View structure with Cn3D
Jiyao W et al.(2023). "The conserved domain database in 2023.",