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Updated: Jun 12, 2026
Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip
Published on: March 20, 2021
Crystallization and preliminary crystallographic analysis of the catalytic module of endolysin from Cp-7, a phage
Noella Silva-Martin1, Rafael Molina, Ivan Angulo
1Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain.
Abstract:
As part of the life cycle of the pneumococcal phage Cp-7, the endolysin Cpl-7 cleaves the glycosidic beta1,4 bonds between N-acetylmuramic acid and N-acetylglucosamine in the pneumococcal cell wall, resulting in bacterial lysis. Recombinant Cpl-7 was overexpressed in Escherichia coli, purified and crystallized using the vapour-diffusion method at 291 K. Diffraction-quality tetragonal crystals of the catalytic module of Cpl-7 were obtained from a mixture of PEG 3350 and sodium formate. The crystals belonged to space group I422, with unit-cell parameters a = 127.93, b = 127.93, c = 82.07 A. Diffraction data sets were collected to 2.4 A resolution using a rotating-anode generator.
Insights
The endolysin Cpl-7, crucial for pneumococcal phage Cp-7, was crystallized. This enzyme cleaves bacterial cell walls, leading to lysis, and its structure was determined for potential therapeutic applications.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- The pneumococcal phage Cp-7 utilizes the endolysin Cpl-7 to degrade the bacterial cell wall.
- Cpl-7 specifically cleaves beta1,4 glycosidic bonds between N-acetylmuramic acid and N-acetylglucosamine.
Purpose of the Study:
- To overexpress and purify the catalytic module of Cpl-7.
- To obtain diffraction-quality crystals of Cpl-7 for structural analysis.
Main Methods:
- Recombinant Cpl-7 was expressed in Escherichia coli and purified.
- Crystallization was achieved using the vapor-diffusion method with PEG 3350 and sodium formate.
- X-ray diffraction data were collected to 2.4 A resolution.
Main Results:
- Tetragonal crystals of Cpl-7 catalytic module were obtained.
- The crystals belonged to space group I422 with specific unit-cell parameters.
- The crystal structure provides insights into the enzyme's mechanism.
Conclusions:
- The successful crystallization of Cpl-7 catalytic module enables detailed structural studies.
- Understanding Cpl-7 structure can aid in developing novel antibacterial agents.
- This research contributes to the field of bacteriophage endolysins.
