Bacillus anthracis Prolyl 4-Hydroxylase Modifies Collagen-like Substrates in Asymmetric Patterns

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• Proline hydroxylation is crucial for collagen stability and function.
• Prolyl 4-hydroxylases (P4Hs) are iron-dependent dioxygenases catalyzing this modification.
• Bacterial P4Hs typically use free proline, unlike animal/plant P4Hs.

Purpose of the Study:

• To elucidate the substrate specificity and catalytic mechanism of Bacillus anthracis prolyl 4-hydroxylase (BaP4H).
• To investigate the structural basis for BaP4H activity.
• To understand the role of BaP4H in bacterial collagen modification.

Main Methods:

• Mass spectrometry
• Fluorescence binding assays
• X-ray crystallography
• Molecular docking

Main Results:

• BaP4H specifically hydroxylates peptidyl proline, not free proline.
• BaP4H exhibits unique hydroxylation patterns on collagen-derived peptides.
• Crystal structures reveal distinct enzyme conformations linked to the catalytic cycle.

Conclusions:

• BaP4H functions as a peptidyl proline hydroxylase, distinct from other bacterial P4Hs.
• Structural insights into BaP4H provide a model for collagen P4Hs and poly-L-proline helix interactions.
• Clarifies the enzymatic role of BaP4H in post-translational modification.