{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nNTAQ1 (N‐terminal glutamine amidohydrolase 1) is a key enzyme in the N‐end rule pathway for protein degradation, where the identity of a protein’s N‐terminal residue determines its half‐life. NTAQ1 catalyzes the deamination of proteins bearing an N‐terminal glutamine, converting it into glutamate. This modification creates a destabilizing residue that marks the protein for ubiquitination and subsequent proteasomal degradation. Structural studies reveal that human NTAQ1 is a monomeric globular protein with an alpha–beta–alpha sandwich architecture. Its active site harbors a highly conserved catalytic triad (Cys–His–Asp), which acts analogously to the catalytic mechanism of cysteine proteases. In addition, the structure shows that a peptide backbone recognition patch forms nonspecific interactions with the substrate’s N‐terminal region, ensuring proper alignment for deamination."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Mi Seul Park, Eduard Bitto, Kyung Rok Kim, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Crystal structure of human protein N-terminal glutamine amidohydrolase, an initial component of the N-end rule pathway."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PLoS One (2014)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1371/journal.pone.0111142"}], "href": "https://doi.org/10.1371/journal.pone.0111142"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "25356641"}], "href": "https://pubmed.ncbi.nlm.nih.gov/25356641"}]}]}]}