The Chlamydomonas cell wall degrading enzyme, lysin, acts on two substrates within the framework of the wall

S. H. Imam, W. J. Snell

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

The Chlamydomonas cell wall is a multilayered, extracellular matrix containing 20-25 proteins and glycoproteins, many of which are highly enriched in hydroxyproline. 80-90% of the wall protein is located in a crystalline portion of the wall that is soluble in sarkosyl-urea solutions as well as in chaotropic salts. Although the wall has no cellulose it contains a noncrystalline, highly insoluble framework portion that is responsible for the integrity and overall shape of the wall. In the present report we show that the framework of the wall is composed of two components that are acted upon by lysin, a wall degrading enzyme released by mating gametes. One, which makes up the major portion of the framework, is insoluble upon boiling in SDS-PAGE sample buffer. Lysin treatment of this portion leads to its physical degradation and the concomitant appearance of several SDS-dithiothreitol-soluble polypeptides ranging in relative molecular mass from >400,000 to <60,000. The second component is the flagellar collar. This hollow cylinder composed of striated fibers aligned in parallel array serves as the tunnel in the wall through which the flagella protrude. Our evidence indicates that the primary collar polypeptide is a 225,000-M(r) molecule that itself has at least two functional domains. One domain, contained in a 185,000-M(r) fragment, permits the self-association of the molecules to form the main body of the collar. The second part of the molecule anchors the collar to the wall framework via sarkosyl-urea-insensitive, SDS-dithiothreitol-sensitive linkages.

Original languageEnglish (US)
Pages (from-to)2211-2221
Number of pages11
JournalJournal of Cell Biology
Volume106
Issue number6
DOIs
StatePublished - 1988

ASJC Scopus subject areas

  • Cell Biology

Fingerprint Dive into the research topics of 'The Chlamydomonas cell wall degrading enzyme, lysin, acts on two substrates within the framework of the wall'. Together they form a unique fingerprint.

  • Cite this