Isodityrosine cross-linking mediates insolubilization of cell walls in Chlamydomonas

• Published in: The Plant cell Vol. 5; no. 7; pp. 809 - 820
• Main Authors: Waffenschmidt, S, Woessner, J.P, Beer, K, Goodenough, U.W
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.07.1993
• Subjects: Amino Acid Sequence; Amino acids; Animals; Ascorbic Acid - metabolism; Base Sequence; Biological and medical sciences; Cell physiology; Cell Wall - metabolism; Cell walls; Cells, cell elements: structure and function; Chlamydomonas reinhardtii - genetics; Chlamydomonas reinhardtii - metabolism; CHLOROPHYCEAE; Cloning, Molecular; Complementary DNA; Cross-Linking Reagents; Detergents; Enzymes; Epitopes; EXPRESION GENICA; EXPRESSION DES GENES; Fundamental and applied biological sciences. Psychology; GLICOPROTEINAS; GLYCOPROTEINE; Glycoproteins; Glycoproteins - genetics; Glycoproteins - immunology; Glycoproteins - metabolism; Hydrogen Peroxide - metabolism; INHIBICION; INHIBITION; Messenger RNA; Molecular Sequence Data; PARED CELULAR; PAROI CELLULAIRE; PEPTIDE; PEPTIDOS; PEROXIDASAS; Peroxidase - metabolism; PEROXIDO DE HIDROGENO; PEROXYDASE; PEROXYDE D'HYDROGENE; Plant cells; Plant physiology and development; Plants; RNA, Messenger - analysis; SECUENCIA NUCLEICA; SEQUENCE NUCLEIQUE; SOLUBILIDAD; SOLUBILITE; Solubility; Somatic cells; TIROSINA; TYROSINE; Tyrosine - analogs & derivatives; Tyrosine - biosynthesis; Tyrosine - metabolism; Tyrosine; Enzyme; Algae; Chlorophycophyta; Insolubilization; Crosslinking; Glycoproteins; Hydroxyproline rich glycoprotein; Mechanism; Cell wall; Chlamydomonas reinhardtii; Peroxidase; Thallophyta
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.5.7.809

Enzymatic removal of the cell wall induces vegetative Chlamydomonas reinhardtii cells to transcribe wall genes and synthesize new hydroxyproline-rich glycoproteins (HRGPs) related to the extensins found in higher plant cell walls. A cDNA expression library made from such induced cells was screened with antibodies to an oligopeptide containing the (SP)x repetitive domains found in Chlamydomonas wall proteins. One of the selected cDNAs encodes an (Sp)x-rich polypeptide that also displays a repeated YGG motif. Ascorbate, a peroxidase inhibitor, and tyrosine derivatives were shown to inhibit insolubilization of both the vegetative and zygotic cell walls of Chlamydomonas, suggesting that oxidative crosslinking of tyrosines is occurring. Moreover, insolubilization of both walls was concomitant with a burst in H2O2 Production and in extracellular peroxidase activity. Finally, both isodityrosine and dityrosine were found in hydrolysates of the insolubilized vegetative wall layer. We propose that the formation of tyrosine cross-links is essential to Chlamydomonas HRGP insolubilization