POLYSACCHARIDE-PROTEIN COMPLEXES 223 



teins I and II with antisera to pneumococcus and Salmonella typhi 

 have been carried out by Heidelberger. Negative reactions with 

 both GMP-I and -II in type II pneumococcus antiserum indicated 

 the absence of a-1, 6 or a-1, 4 Hnkages, whereas stronglv positive 

 cross-reactions in type VIII antiserum with GMP-I indicate the 

 presence of yS-1, 4 glycosidic hnkages. A stronglv positive cross- 

 reaction in this antiserum was also obtained with lies glucomannan 

 (Heidelberger and Rebers, 1958), from which a cellobiose moiety 

 has been obtained on partial hydrolvsis (Smith and Srivastava, 

 1956). In contrast, GMP-II showed little, if any, cross-reaction with 

 the t\pe VIII antiserum. It is, therefore, of considerable interest to 

 note that yeast "mannan," obtained by hot alkaline extraction pro- 

 cedures, has not been found to cross-react with any pneumococcal 

 antiserum (Heidelberger, 1959). Both GMP-I and -II also gave 

 strongly positive cross-reactions in typhoid antiserum, as had been 

 found previously for yeast "mannan" (Heidelberger and Cordoba, 

 1956). 



Additional evidence against the presence of a-pyranose deriva- 

 tives in glucomannan-protein I is provided by infrared absorption 

 spectra. Barker et al. ( 1956 ) have shown that a-pyranose residues 

 absorb strongly at 844 cm~^ and /3-pyranose derivatives absorb at 

 about 890 cm \ Examination of Fig. 13 reveals practically no ab- 

 sorption in the 844 cm~^ region by GMP-I, but significant absorp- 

 tion by GMP-II. On the other hand, GMP-I exhibits a small peak 

 at 890 cm"^ which is not shown by GMP-II. 



Bonding Between Polysaccharide and Protein. A thoroughly 

 washed, clean cell-wall preparation does not leach out material on 

 standing in water. This insolubility of the wall is in sharp contrast 

 to the solubility of GMP-1 and -II in water. Glucan is the insoluble 

 polysaccharide component of the wall to which the soluble com- 

 ponents are bound. The high content of acidic amino acids in the 

 protein components of the wall fractions immediately suggests that 

 protein and polysaccharide mav be joined through ester linkage. 

 This possibility is being explored through studies of infrared spectra, 

 and of the hydroxylamine ester-cleavage reaction. It is not yet pos- 

 sible to assess quantitatively the relative contributions of ester link- 

 age (or other covalent linkage) and hydrogen-bonding in uniting 

 the various components of the wall together to form the complex 

 wall structure, but some understanding of this union may be forth- 

 coming in the near future. 



