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Galactans from Cryptonemia species. Part II: studies on the system of galactans of Cryptonemia seminervis (Halymeniales) and on the structure of major fractions.
Carbohydr Res. 2009 Nov 23; 344(17):2364-74.CR

Abstract

Cryptonemia seminervis biosynthesizes a family of D,L-hybrid galactans based on the classical 3-linked beta-D-galactopyranosyl-->4-linked alpha-D- and alpha-L-galactopyranosyl alternating sequence (A-units-->B-units) with major amounts of alpha-D- and alpha-L-galactose and 3,6-anhydro-D- and L-galactose and lesser percentages of 3,6-anhydro-2-O-methyl-L-galactose, 2-O-methyl-, 4-O-methyl- and 6-O-methylgalactoses. The dispersion of structures in this family is based on five structural factors, namely: (a) the amount and position of substituent groups as sulfate (major), pyruvic acid ketals, methoxyl and glycosyl side-chain (4-O-methyl galactopyranosyl and/or xylosyl); (b) the ratio galactose/3,6-anhydrogalactose in the B-units; (c) the ratio D,L-galactoses and D,L-3,6-anhydrogalactoses also in the B-units, (d) the formation of diads and (e) the sequence of the diads in the linear backbone. Considering these variables it is not unexpected to find in the fractions studied at least 18 structural units producing highly complex structures. Structural studies carried out in two major fractions (S2S-3 and S2S-4) showed that these galactans were formed mainly by beta-D-galactopyranosyl 2-sulfate (20 and 11.9 mol%), beta-d-galactopyranosyl 2-sulfate 4,6-O-(1'-carboxyethylidene) (8.9 and 6.0 mol%) and beta-D-galactopyranosyl 2,6-sulfate (5.4 and 18.6 mol%), together with 3,6-anhydro-alpha-l-galactopyranosyl (11.4 and 7.3 mol%) and 3,6-anhydro-alpha-L-galactopyranosyl 2-sulfate (4.9 and 15.4 mol%) and minor quantities of 12-15 other structural units. Preparative alkaline treatment carried out on fraction (S2S-3) produced a quantitative formation of 3,6-anhydro alpha-L-galactopyranosyl units from precursor units (alpha-L-galactose 6-sulfate and alpha-L-galactose 2,6-sulfate). Kinetic studies on this 3,6-anhydro cyclization show a rate constant of 5.2 x 10(4)s(-1) indicating diads of the type G-->L6S/2,6S. Data from chemical, spectroscopic and kinetic studies suggest that, in S2S-3, the agaran block in the D,L-hybrid galactan is composed of the following diads: G(6R)-->L6S/2,6S and G2S(P)(2,6S)-->LA(2S)(2R)(2M) and the carrageenan block of G2S(P)-->D(2S)(2,3S)(3S)(3,6S) in a molar ratio of agaran to carrageenan structures of approximately 2:1.

Authors+Show Affiliations

Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, PO Box: 19046, CEP: 81531-990, Curitiba, Paraná, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19800614

Citation

Zibetti, Rosiane G M., et al. "Galactans From Cryptonemia Species. Part II: Studies On the System of Galactans of Cryptonemia Seminervis (Halymeniales) and On the Structure of Major Fractions." Carbohydrate Research, vol. 344, no. 17, 2009, pp. 2364-74.
Zibetti RG, Duarte ME, Noseda MD, et al. Galactans from Cryptonemia species. Part II: studies on the system of galactans of Cryptonemia seminervis (Halymeniales) and on the structure of major fractions. Carbohydr Res. 2009;344(17):2364-74.
Zibetti, R. G., Duarte, M. E., Noseda, M. D., Colodi, F. G., Ducatti, D. R., Ferreira, L. G., Cardoso, M. A., & Cerezo, A. S. (2009). Galactans from Cryptonemia species. Part II: studies on the system of galactans of Cryptonemia seminervis (Halymeniales) and on the structure of major fractions. Carbohydrate Research, 344(17), 2364-74. https://doi.org/10.1016/j.carres.2009.09.003
Zibetti RG, et al. Galactans From Cryptonemia Species. Part II: Studies On the System of Galactans of Cryptonemia Seminervis (Halymeniales) and On the Structure of Major Fractions. Carbohydr Res. 2009 Nov 23;344(17):2364-74. PubMed PMID: 19800614.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Galactans from Cryptonemia species. Part II: studies on the system of galactans of Cryptonemia seminervis (Halymeniales) and on the structure of major fractions. AU - Zibetti,Rosiane G M, AU - Duarte,Maria E R, AU - Noseda,Miguel D, AU - Colodi,Franciely G, AU - Ducatti,Diogo R B, AU - Ferreira,Luciana G, AU - Cardoso,Marco A, AU - Cerezo,Alberto S, Y1 - 2009/09/06/ PY - 2009/06/17/received PY - 2009/09/01/revised PY - 2009/09/02/accepted PY - 2009/10/6/entrez PY - 2009/10/6/pubmed PY - 2010/1/8/medline SP - 2364 EP - 74 JF - Carbohydrate research JO - Carbohydr Res VL - 344 IS - 17 N2 - Cryptonemia seminervis biosynthesizes a family of D,L-hybrid galactans based on the classical 3-linked beta-D-galactopyranosyl-->4-linked alpha-D- and alpha-L-galactopyranosyl alternating sequence (A-units-->B-units) with major amounts of alpha-D- and alpha-L-galactose and 3,6-anhydro-D- and L-galactose and lesser percentages of 3,6-anhydro-2-O-methyl-L-galactose, 2-O-methyl-, 4-O-methyl- and 6-O-methylgalactoses. The dispersion of structures in this family is based on five structural factors, namely: (a) the amount and position of substituent groups as sulfate (major), pyruvic acid ketals, methoxyl and glycosyl side-chain (4-O-methyl galactopyranosyl and/or xylosyl); (b) the ratio galactose/3,6-anhydrogalactose in the B-units; (c) the ratio D,L-galactoses and D,L-3,6-anhydrogalactoses also in the B-units, (d) the formation of diads and (e) the sequence of the diads in the linear backbone. Considering these variables it is not unexpected to find in the fractions studied at least 18 structural units producing highly complex structures. Structural studies carried out in two major fractions (S2S-3 and S2S-4) showed that these galactans were formed mainly by beta-D-galactopyranosyl 2-sulfate (20 and 11.9 mol%), beta-d-galactopyranosyl 2-sulfate 4,6-O-(1'-carboxyethylidene) (8.9 and 6.0 mol%) and beta-D-galactopyranosyl 2,6-sulfate (5.4 and 18.6 mol%), together with 3,6-anhydro-alpha-l-galactopyranosyl (11.4 and 7.3 mol%) and 3,6-anhydro-alpha-L-galactopyranosyl 2-sulfate (4.9 and 15.4 mol%) and minor quantities of 12-15 other structural units. Preparative alkaline treatment carried out on fraction (S2S-3) produced a quantitative formation of 3,6-anhydro alpha-L-galactopyranosyl units from precursor units (alpha-L-galactose 6-sulfate and alpha-L-galactose 2,6-sulfate). Kinetic studies on this 3,6-anhydro cyclization show a rate constant of 5.2 x 10(4)s(-1) indicating diads of the type G-->L6S/2,6S. Data from chemical, spectroscopic and kinetic studies suggest that, in S2S-3, the agaran block in the D,L-hybrid galactan is composed of the following diads: G(6R)-->L6S/2,6S and G2S(P)(2,6S)-->LA(2S)(2R)(2M) and the carrageenan block of G2S(P)-->D(2S)(2,3S)(3S)(3,6S) in a molar ratio of agaran to carrageenan structures of approximately 2:1. SN - 1873-426X UR - https://www.unboundmedicine.com/medline/citation/19800614/Galactans_from_Cryptonemia_species__Part_II:_studies_on_the_system_of_galactans_of_Cryptonemia_seminervis__Halymeniales__and_on_the_structure_of_major_fractions_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0008-6215(09)00424-8 DB - PRIME DP - Unbound Medicine ER -