OGFOD3

Model summary

A soluble Fe(II)/2-oxoglutarate-dependent oxygenase that installs 4-hydroxyproline on protein substrates. Its catalytic core uses iron and 2-oxoglutarate to hydroxylate proline residues, thereby tuning protein stability and interaction properties. Although intrinsically soluble, it likely operates near membranes by docking onto membrane-proximal assemblies to access its targets, coupling localized hydroxylation to broader cellular pathways.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture.

   The polypeptide is covered end-to-end by IPR039210 (2-oxoglutarate and iron-dependent oxygenase domain-containing protein 3 family, residues 1–318), establishing membership in a conserved oxygenase family. Within this scaffold, IPR006620 (Prolyl 4-hydroxylase, alpha subunit domain, residues 108–306) defines a canonical prolyl 4-hydroxylase-like core that specializes in post-translational modification of proline residues in proteins. Nested more distally, IPR005123 (Oxoglutarate/iron-dependent dioxygenase domain, residues 207–309) and IPR044862 (Prolyl 4-hydroxylase alpha subunit, Fe(2+) 2OG dioxygenase domain, residues 223–303) pinpoint the catalytic heart: a Fe(II)/2-oxoglutarate (2OG)-dependent dioxygenase module. The ordered layout—an N-terminal family envelope, a central prolyl 4-hydroxylase-like domain, and a tightly defined Fe(II)/2OG catalytic core—causally dictates a chemistry that uses Fe(II) and 2OG to hydroxylate peptidyl-proline, releasing succinate and CO2.

2. 02

   This domain architecture compels a molecular function of peptidyl-proline 4-dioxygenase activity (GO:0031545) and more generally a 2-oxoglutarate-dependent dioxygenase activity (GO:0016706).

   The prolyl 4-hydroxylase-like fold (IPR006620) and the Fe(II)/2OG catalytic center (IPR005123, IPR044862) together specify site-selective hydroxylation of proline side chains in protein substrates. Such chemistry directly drives the biological process of peptidyl-proline hydroxylation (GO:0019511), a modification that tunes protein stability, folding, and interaction surfaces.

3. 03

   The absence of transmembrane helices in the annotated domains suggests a soluble enzyme, yet the functional context and cellular component label indicate membrane association.

   A parsimonious explanation is peripheral or transient membrane association via protein–protein interactions that recruit the soluble Fe(II)/2OG enzyme to membrane-proximal assemblies. This reasoning supports a membrane localization (GO:0016020), plausibly at cytoplasmic-facing membranes where substrate proteins and assembly factors concentrate.

4. 04

   Mechanistically, the enzyme binds Fe(II) and 2OG within the IPR044862-defined pocket, activates O2 to form a ferryl intermediate, and inserts a hydroxyl group at the 4-position of peptidyl-proline.

   This reaction modifies target proteins and can nucleate higher-order assemblies. From this, I hypothesize that the enzyme transiently associates with membrane-proximal protein complexes—such as cytoskeletal or trafficking hubs—to access substrates. Likely interaction partners include proline-rich membrane-associated proteins and scaffolds that localize hydroxylase chemistry near membranes. Such assemblies would stabilize the enzyme at the membrane interface and channel modified substrates into downstream pathways.