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Confirmation of a cellulose-like structure for the glucan sulphate of buccinum undatum L.
NOTES
259
REFERENCES 1 J. C. SO-EN,
2 3 4 5 6 7 8 9 10
Advazz. Carbohydrate Chem., 6 (1951) 316; J. C. SOWDEN AND D. R. STROBACH, J- Am. Chem. Sot., 80 (1958) 2532. B.A. MCFADDEN,L.L.BARDEN,N. W.ROKKE, M. UYEDA,ANDT. J. SIEK, J. Am. CJzem_SOC., 87 (1965) 5505. J. S. FRUTON AND S. SIMMONDS, General Biochemistry, John Wiley and Sons, Inc., New York, 1958, pp. 530 and 551-552. B. L. HORECKER, Metlzods Ezzzymol., (1957) 195-197. J. R. SOKATCHAND B.A. MCFADDEN, Bioclzem.Prepzz., in press. B. L. HORECKER, Methods Enzymol., 3 (1957) 105-107. E. RACKER, IN H. U. BERGhlEYER (Ed.), Metizods in Enzymatic Analysis, Academic Press Inc., New York, 1963, pp. 107-110. Z. DISCHE, J. Biol. Chem., 204 (1953) 983. J. C. SOWDEN AND R. SCHAFFER, J. Am. Clzem. Ser., 74 (1952) 499. D. M. BROXVN AND A. R. TODD, J. C/zem. Sot., (1952) 52.
(Received October 3rd, 1966; in revisedform, December 27th, 1966) Carbofzyd. Res., 4 (1967) 254-259
Confirmation of a cellulose-like of Buccinum undatum L.
structure
for the giucan sulphate
Hunt and Jevons’ recently described the isolation and characterization of a glucan sulphate from the hypobranchial mucin of the whelk Buccinunz zmdatunz L. The main glycosidic linkages of this mucopolysaccharide were thought to be P-D-( l-+4). The polysaccharide would thus be similar to cellulose were it not for the sulphation of the glucose residues. Evidence for this came from studies of the desulphated polysaccharide by infrared spectroscopy, partial hydrolysis with acid, and enzymic degradation. In the present study by X-ray diffraction, further weight has been added to the earlier deductions of a cellulose-like structure for the desulphated glucan. For purposes of comparison, X-ray diffraction patterns of both the desulphated polysaccharide and of a powdered viscose rayon were prepared. Preliminary examination of the polysaccharide showed the presence of spurious, sharp diffractions possibly arising from a contaminant produced during the desulphation process. Treatment of the polysaccharide with 10% EDTA for 36 h eliminated most of these additional diiractions.
The X-ray diagrams are shown in Fig. 1.
Rings 1 and 3, which are neazly the same in both diffraction diagrams, are reflections due to the regular, side-to-side packing of cellulose chains, i.e., 101 and 002, Carbolzyd. Res., 4 (1967) 259-261
260
NOTES
respectively. Ring 2 consists of two main contributions; one of these arises from the side-to-side packing only, IOl, whereas the other is 021 having a component due to chain-length repeats. In contrast to rings 1 and 3, ring 2 appears stronger in the viscose diagram A; this indicates a greater number of planes giving rise to the 021 reflection,
Fig. 1. X-ray powder diagrams of A, viscose rayon; B, desulphated poiysaccharide
from hypo-
branchial mucin of Buccinnnz undarttm.
and hence a greater chain-length. Outer lines in the diagrams are largely influenced by chain-length characteristics, and are much less well-defined in the desulphated polysaccharide B. However, in the case of ring 4, there are contributions from different planes, some of which [(312), (013), (3II)] lie more nearly parallel to the chain axis. Carbohyd. Res., 4 (1967) 259-261
261
NOTES
The lack of definition in chain-length branching or occasional (143)-linkage’. spectrum
of the desulphated
as may also the insolubility
diffractions may arise in part from occasional The absorption at 790 cm-’ in the infrared
polysaccharide in cuprammonium
may be associated solution’.
with such branching,
The apparent,
short length
of extended chains in crystalline regions may be due to extensive folding or other changes in conformation, since, unlike the viscose rayon used for comparison in A, the pclysaccharide
chains
in B would not be drawn out during preparation.
Never-
theless, in thin flakes of the desulphated polysaccharide precipitate, there are conspicuous, positively birefringent, fibrous regions, and preliminary X-ray tests on these show that typical fibre diagrams should be obtained. Detailed comparisons of oriented viscose and oriented polysaccharide seem possible, and would provide better information about the chain-length characteristics in the latter. However, the diffraction diagrams demonstrate that the dominant structure is of a that of hydrated or regenerated cellulose, i.e.‘, cellulose II. This confirmation cellulose-like structure raises questions concerning the biosynthesis of the polysaccharide sulphate. As b-( l-+4)-linked polymers of D-&COSC become increasingly insoluble with increasing chain-length, it seems likely that the sulphation precedes, or closely accompanies, formation of the glycosidic bonds.
S. HUFST
Department of Biological Chemistry, Unitersits of Manchester, Manchester (Great Britain) T/te Astbury Department of Biophysics, The University, Leeds 2 (Great Britain)
1 S. HUNT AND F. R. JEVONS, Biochem. J., 98 (1966) 522. 2 W. A. SISSGN, IN E. OTT (Ed.), Celllrlose and Celhdose 1943, p. 203.
K. M. RUDALL
Dericatices,
Interscience,
New York,
(Received November 26th. 1966) Carbohyd. Res., 4 (1967) 259-261
259
REFERENCES 1 J. C. SO-EN,
2 3 4 5 6 7 8 9 10
Advazz. Carbohydrate Chem., 6 (1951) 316; J. C. SOWDEN AND D. R. STROBACH, J- Am. Chem. Sot., 80 (1958) 2532. B.A. MCFADDEN,L.L.BARDEN,N. W.ROKKE, M. UYEDA,ANDT. J. SIEK, J. Am. CJzem_SOC., 87 (1965) 5505. J. S. FRUTON AND S. SIMMONDS, General Biochemistry, John Wiley and Sons, Inc., New York, 1958, pp. 530 and 551-552. B. L. HORECKER, Metlzods Ezzzymol., (1957) 195-197. J. R. SOKATCHAND B.A. MCFADDEN, Bioclzem.Prepzz., in press. B. L. HORECKER, Methods Enzymol., 3 (1957) 105-107. E. RACKER, IN H. U. BERGhlEYER (Ed.), Metizods in Enzymatic Analysis, Academic Press Inc., New York, 1963, pp. 107-110. Z. DISCHE, J. Biol. Chem., 204 (1953) 983. J. C. SOWDEN AND R. SCHAFFER, J. Am. Clzem. Ser., 74 (1952) 499. D. M. BROXVN AND A. R. TODD, J. C/zem. Sot., (1952) 52.
(Received October 3rd, 1966; in revisedform, December 27th, 1966) Carbofzyd. Res., 4 (1967) 254-259
Confirmation of a cellulose-like of Buccinum undatum L.
structure
for the giucan sulphate
Hunt and Jevons’ recently described the isolation and characterization of a glucan sulphate from the hypobranchial mucin of the whelk Buccinunz zmdatunz L. The main glycosidic linkages of this mucopolysaccharide were thought to be P-D-( l-+4). The polysaccharide would thus be similar to cellulose were it not for the sulphation of the glucose residues. Evidence for this came from studies of the desulphated polysaccharide by infrared spectroscopy, partial hydrolysis with acid, and enzymic degradation. In the present study by X-ray diffraction, further weight has been added to the earlier deductions of a cellulose-like structure for the desulphated glucan. For purposes of comparison, X-ray diffraction patterns of both the desulphated polysaccharide and of a powdered viscose rayon were prepared. Preliminary examination of the polysaccharide showed the presence of spurious, sharp diffractions possibly arising from a contaminant produced during the desulphation process. Treatment of the polysaccharide with 10% EDTA for 36 h eliminated most of these additional diiractions.
The X-ray diagrams are shown in Fig. 1.
Rings 1 and 3, which are neazly the same in both diffraction diagrams, are reflections due to the regular, side-to-side packing of cellulose chains, i.e., 101 and 002, Carbolzyd. Res., 4 (1967) 259-261
260
NOTES
respectively. Ring 2 consists of two main contributions; one of these arises from the side-to-side packing only, IOl, whereas the other is 021 having a component due to chain-length repeats. In contrast to rings 1 and 3, ring 2 appears stronger in the viscose diagram A; this indicates a greater number of planes giving rise to the 021 reflection,
Fig. 1. X-ray powder diagrams of A, viscose rayon; B, desulphated poiysaccharide
from hypo-
branchial mucin of Buccinnnz undarttm.
and hence a greater chain-length. Outer lines in the diagrams are largely influenced by chain-length characteristics, and are much less well-defined in the desulphated polysaccharide B. However, in the case of ring 4, there are contributions from different planes, some of which [(312), (013), (3II)] lie more nearly parallel to the chain axis. Carbohyd. Res., 4 (1967) 259-261
261
NOTES
The lack of definition in chain-length branching or occasional (143)-linkage’. spectrum
of the desulphated
as may also the insolubility
diffractions may arise in part from occasional The absorption at 790 cm-’ in the infrared
polysaccharide in cuprammonium
may be associated solution’.
with such branching,
The apparent,
short length
of extended chains in crystalline regions may be due to extensive folding or other changes in conformation, since, unlike the viscose rayon used for comparison in A, the pclysaccharide
chains
in B would not be drawn out during preparation.
Never-
theless, in thin flakes of the desulphated polysaccharide precipitate, there are conspicuous, positively birefringent, fibrous regions, and preliminary X-ray tests on these show that typical fibre diagrams should be obtained. Detailed comparisons of oriented viscose and oriented polysaccharide seem possible, and would provide better information about the chain-length characteristics in the latter. However, the diffraction diagrams demonstrate that the dominant structure is of a that of hydrated or regenerated cellulose, i.e.‘, cellulose II. This confirmation cellulose-like structure raises questions concerning the biosynthesis of the polysaccharide sulphate. As b-( l-+4)-linked polymers of D-&COSC become increasingly insoluble with increasing chain-length, it seems likely that the sulphation precedes, or closely accompanies, formation of the glycosidic bonds.
S. HUFST
Department of Biological Chemistry, Unitersits of Manchester, Manchester (Great Britain) T/te Astbury Department of Biophysics, The University, Leeds 2 (Great Britain)
1 S. HUNT AND F. R. JEVONS, Biochem. J., 98 (1966) 522. 2 W. A. SISSGN, IN E. OTT (Ed.), Celllrlose and Celhdose 1943, p. 203.
K. M. RUDALL
Dericatices,
Interscience,
New York,
(Received November 26th. 1966) Carbohyd. Res., 4 (1967) 259-261