Analysis of E. coli K5 capsular polysaccharide heparosan

Area of Science:

• Biotechnology
• Polymer Chemistry
• Biochemistry

Background:

• Heparosan is a crucial precursor for synthesizing bioengineered heparin.
• Bioengineered heparin offers a potential alternative to porcine intestinal heparin, an anticoagulant drug.
• Understanding heparosan's molecular weight is vital for its application in drug development.

Purpose of the Study:

• To investigate the molecular weight (MW) distribution of heparosan produced via E. coli K5 fermentation.
• To establish a method for determining heparosan MW and polydispersity.
• To create heparosan MW standards for accurate analysis.

Main Methods:

• Utilized large-slab isocratic and mini-slab gradient polyacrylamide gel electrophoresis (PAGE) for MW and polydispersity analysis.
• Employed continuous-elution PAGE for preparative fractionation and isolation of heparosan MW standards.
• Determined the MW of heparosan standards using electrospray ionization Fourier-transform mass spectrometry (ESI-FT-MS).

Main Results:

• Successfully generated heparosan MW standards through preparative PAGE and ESI-FT-MS.
• Established a ladder of standards to accurately determine the MW properties of polydisperse heparosan samples.
• Found that both unbleached and bleached heparosan from E. coli K5 fermentation displayed comparable number-averaged MWs (M(N)), weight-averaged MWs (M(W)), and MW ranges (3,000–150,000 Da).

Conclusions:

• The developed methods enable precise characterization of heparosan molecular weight distribution.
• Heparosan produced by E. coli K5 fermentation exhibits a consistent MW profile regardless of bleaching.
• These findings support the use of fermented heparosan in the development of bioengineered heparin therapeutics.