PRIMARY STRUCTURE AND EXPRESSION OF A GAMETE LYTIC ENZYME IN CHLAMYDOMONAS-REINHARDTII - SIMILARITY OF FUNCTIONAL DOMAINS TO MATRIX METALLOPROTEASES

被引:82
作者
KINOSHITA, T
FUKUZAWA, H
SHIMADA, T
SAITO, T
MATSUDA, Y
机构
[1] KOBE UNIV,FAC SCI,DEPT BIOL,KOBE 657,JAPAN
[2] KYOTO UNIV,FAC AGR,DEPT AGR CHEM,PLANT MOLEC BIOL LAB,KYOTO 60601,JAPAN
关键词
COLLAGENASE FAMILY; EXTRACELLULAR MATRIX; PERIPLASM; PREPROENZYME FORM; ZINC BINDING SITE;
D O I
10.1073/pnas.89.10.4693
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
A gamete lytic enzyme (GLE) of Chlamydomonas reinhardtii is a zinc metalloprotease and mediates digestion of the cell walls of the two mating-type gametes during mating as a necessary prelude to cell fusion. The nucleotide sequence analysis of a cDNA revealed that GLE is synthesized in a preproenzyme form, a 638-amino acid polypeptide (M(r), 69,824) with a 28-amino acid signal peptide, a 155-amino acid propolypeptide, and a 455 -amino acid mature polypeptide (M(r), 49,633). A potential site for autocatalytic activation was contained within the propolypeptide and a zinc binding site found within the mature polypeptide; both sites were highly homologous to those in mammalian collagenase. A putative calcium binding site was present in the near C-terminal region of the mature GLE. Both propolypeptide and mature polypeptide had potential sites for asparagine-linked glycosylation, and the Arg-(Pro)3 and Arg-(Pro)2 motifS, which are known to exist in hydroxyproline-rich glycoproteins of the Chlamydomonas cell wall. Northern blot analysis revealed that steady-state levels of the 2.4-kilobase GLE mRNA increased during growth and mitotic cell division in the vegetative cell cycle and also increased markedly during gametogenesis under nitrogen-starved conditions.
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页码:4693 / 4697
页数:5
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