Crystal structure of a polyglycine hydrolase determined using a RoseTTAFold model

Area of Science:

• Biochemistry
• Structural Biology
• Mycology

Background:

• Polyglycine hydrolases (PGHs) are secreted fungal proteases.
• PGHs degrade plant defense proteins like Zea mays ChitA, aiding fungal infection.
• No prior structural data existed for PGHs, hindering mechanistic understanding.

Purpose of the Study:

• To structurally and biochemically characterize polyglycine hydrolases.
• To elucidate the proteolytic mechanism of PGHs.
• To understand the evolutionary relationships of PGHs.

Main Methods:

• X-ray crystallography was employed to determine the atomic structure.
• RoseTTAFold, a computational tool, was utilized for initial model generation.
• Biochemical assays were performed to investigate enzyme activity.

Main Results:

• The first atomic structure of a polyglycine hydrolase was determined.
• PGHs possess a unique two-domain structure: a novel N-domain and a C-domain homologous to β-lactamases.
• A catalytic nucleophilic serine was identified in the C-domain, common to β-lactamases.

Conclusions:

• The study provides the first structural insights into the PGH family.
• PGHs share structural and potentially functional similarities with class C β-lactamases.
• Integrating computational methods with experimental structure determination accelerates biological discovery.