TRACHEOBRONCHIAL GLYCOPROTEIN STRUCTURE

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Our aim, in this proposal, is to chemically and structurally characterize purified human tracheobronchial glycoproteins. Emphasis is placed on analyzing the major acidic sulfated oligosaccharides and major oligosaccharide-oligopeptide subunits isolated from tracheobronchial glycoproteins. Research on characterizing the sulfated oligosaccharides is stressed since it is primarily this fraction that increases with severity of a lung disease. Tracheobronchial glycoproteins and isolated fractions from patients suffereing from various forms of chronic obstructive pulmonary disease (e.g., chronic bronchitis, asthma, bronchiectasis, alveolar proteinosis and cystic fibrosis (CF) will be studied, mapped and compared so as to gain insight from different pathological vectors on how the tracheobronchial submucosal glands alter their secretory glycoprotein structure in response to chronic disease. Accent is also placed on analyzing the different oligosaccharide-oligopeptide subunits isolated from tracheobronchial glycoproteins. Our preliminary studies strongly suggest that there is definite amino acid sequence in the protein core that codes for sulfation or sialation of the attached oligosaccharide and that there is a difference in the type of oligosaccharide that is glycosidically linked to serine and to threonine. Gas-liquid chromatography and mass spectrometry will be employed in all chemical studies and will include new methods, developed in this laboratory, for the analysis of sulfate, sugar sulfates, sialic acids, amino sugars and amino acids. One possible role for the increased anionicity of these glycoproteins in chronic lung disease is that it renders them to be less susceptible to bacterial enzymatic degradation. We propose to investigate this by studying in vitro the resistance of tracheobronchial glycoproteins, possessing varying degrees of sulfation, to glycosidase attack. To date, we have very little knowledge of the structure and related functions of tracheobronchial glycoproteins. Over the past five years we have isolated and purified all the tracheobronchial glycoproteins, and fraction thereof, to be used in this proposal. Their study will provide important and needed information about the structure and biochemistry of these very important molecules in health and disease.