Sample preparation, crystallization and structure solution of HisC from Mycobacterium tuberculosis.

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Histidinolphosphate aminotransferase (HisC) is essential for histidine biosynthesis in Mycobacterium tuberculosis.
• Understanding the structure of HisC can provide insights into potential drug targets for tuberculosis treatment.

Purpose of the Study:

• To determine the three-dimensional crystal structure of Histidinolphosphate aminotransferase (HisC) from Mycobacterium tuberculosis.
• To characterize the oligomeric state of HisC in crystalline and solution forms.

Main Methods:

• Overexpression and purification of HisC from Mycobacterium tuberculosis in M. smegmatis.
• Crystallization using hanging-drop vapor diffusion with polyethylene glycol monomethyl ether 2000.
• X-ray diffraction data collection to 3.08 Å resolution and structure determination by molecular replacement.

Main Results:

• Diffraction-quality crystals of HisC were obtained and belonged to the hexagonal space group P3221.
• The crystal structure revealed HisC as a dimer in both crystal and solution states.
• The structure was solved using a homologous model from Corynebacterium glutamicum.

Conclusions:

• The determined crystal structure of Mycobacterium tuberculosis HisC provides a structural basis for understanding its function.
• The dimeric nature of HisC is confirmed in both crystal and solution, relevant for its biological activity.
• This structural information may aid in the development of novel inhibitors targeting HisC for anti-tubercular therapies.