Changing arabinosylation patterns of wall-bound hydroxyproline in bean cell cultures

Abstract

The arabinosylation patterns of wall-bound hydroxyproline in Phaseolus vulgaris L. cell suspension cultures were determined by separating free hydroxyproline and hydroxyproline-arabinose oligomers over a Bio-Gel P-2 column. Total hydroxyproline accounted for about 3.3% of wall dry weight during all growth phases of batch-cultured bean cells. The chemical arabinosylation patterns of wall-bound hydroxyproline varied during the lag phase and early log phase of the culture. First, an increase in nonglycosylated hydroxyproline occurred accompanied by a corresponding decrease in hydroxyproline tetra-arabinoside. During the early log phase the reverse happened. In later stages of growth the chemical arabinosylation patterns remained constant. The radiochemical arabinosylation patterns were also determined, after pulselabeling the cultures with [¹⁴C]proline at various times during growth, to be able to distinguish recently incorporated hydroxyproline. The time course of the arabinosylation pattern of this fraction indicated that the initial changes in the chemical pattern were due to the temporary incorporation of less extensively glycosylated hydroxyproline-containing protein into the cell wall.