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54. Structures of the Glycopeptidolpid Antigens from Serovars in the Mycobacterium avium/Mycobacterium intracellalure/Mycobacterium scrofulaceum Serocomplex.

Author

Brennan, Patrick J., Mayer, Hubert, Aspinall, Gerald O., and Shin, Jeong E. Nam

Subjects
ANTIGENS, MYCOBACTERIUM avium, OLIGOSACCHARIDES, IMMUNOGLOBULINS
Abstract

The 'C-mycosidic' glycopeptidolipid typing antigens from all serovars in the Mycobacterium avium/M, intracellulare/M, scrofulaceum complex have been examined to varying extents. Detailed analysis of those from serovars 8, 9, 16 and 25 show that the antigens consist of short acetylated oligosaccharides linked to a common fattyacyl-peptidyl-O-(3,4-di-O-methylrhamnose) 'core'. The oligosaccharide units, in a form suitable for chemical studies, were liberated as oligosaccharide alditols on treatment of the glycopeptidolipids with alkaline borohydride solution. The alditol in the reduced oligosaccharides from all sources is 6-deoxytalitol. Moreover rhamnose is also always present, indicating that a 'basal' disaccharide, rhamnosyl-6-deoxytalosyl, is always linked to the allo-threonine in the acylpeptide. In addition the oligosaccharides from the glycopeptidolipids of each serovar are distinguished by their own individualistic sugars: 3-O-methylglucose in serovar 8; 2,3-di-O-methylfucose in serovar 9; 2-O-methylfucose in serovar 25; 4-O-methylrhamnose in the oligosaccharide from one of the two glycopeptidolipids in serovar 16 and apparently another rhamnosyl substituent in the other oligosaccharide. The glycopeptidolipid antigens in their structural principals, cellular location and physiological role bear a striking miniscular resemblance to cell wall components of other bacteria such as the O-antigenic and R-antigenic lipopolysaccharides. [ABSTRACT FROM AUTHOR]

Published
1981

55. Structure of the glycopeptidolipid antigen of serovar 20 of the Mycobacterium aviumserocomplex, synthesis of allyl glycosides of the outer di- and tri-saccharide units of the antigens of serovars 14 and 20, and serology of the derived neoglycoproteins

Author

Aspinall, Gerald O., Khare, Naveen K., Sood, Ramesh K., Chatterjee, Delphi, Rivoire, Becky, and Brennan, Patrick J.

Abstract

The tetrasaccharide hapten released from the glycopeptidolipid (GPL) antigen of Mycobacterium aviumserovar 20 has been characterized as O-(2-O-methyl-α-d-rhamnopyranosyl)-(1 → 3)-O-(2-O-methyl-α-l-fucopyranosyl)-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-6-deoxy-l-talose. Syntheses are reported of allyl glycosides of the outer disaccharide unit of this hapten, O-(2-O-methyl-α-d-rhamnopyranosyl)-(1 → 3)-2-O-methyl-α-l-fucopyranose, and also of the outer di- and tri-saccharide units of the GPL antigen of M. aviumserovar 14, O-(N-formyl-α-l-kansosaminyl)-(1 → 3)-2-O-methyl-α-d-rhamnopyranose and O-(N-formyl-α-l-kansosaminyl)-(1 → 3)-O-(2-O-methyl-α-d-rhamnopyranosyl-(1 → 3)-2-O-methyl-α-l-fucopyranose. The key steps in the latter synthesis involve the preparation of allyl 4-azido-4,6-dideoxy-3-C-methyl-2-O-methyl-α-l-mannopyranoside as a precursor for the N-formylkansosamine unit, followed sequentially by conversion into and use of a trichloroacetimidate as glycosyl donor for di- and tri-saccharide formation, O-deacylation, reduction, and N-formylation. The allyl glycosides, representative of the haptens from both serovars, have been converted into neoglycoproteins (NGPs) and their serological activities have been compared in the light of the structural relationship between them.

Published
1992
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56. Action of Grignard reagents on hexuronic esters and attempted dehydration of tertiary alcohols to give hex-5-enopyranosides

Author

Aspinall, Gerald O., Igarashi, Osamu, Krishnamurthy, Thinnayam N., Mitura, Walter, and Funabashi, Masuo

Abstract

The attempted formation of hex-5-enopyranosides from glycosiduronates by the action of Grignard reagents followed by dehydration affords hex-6-enopyranosides or 1,6-anhydrohexopyranoses as major products. 13C nmr spectra of 6,6-di-C-substituted hexose derivatives are compared with those of a number of structurally related compounds. The formation of a hex-5-enopyranoside and the selective cleavage of its glycosidic linkage is illustrated by the synthesis and controlled hydrolysis of methyl 6-O-(6-deoxy-2,3,4-tri-O-methyl-β-L-arabino-hex-5-enopyranosyl)-2,3,4-tri-O-methyl-β-D-glucopyranoside(2).

Published
1976
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86. Book Review

Author

Aspinall, Gerald O.

Published
1978

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