Polypeptides of the maize amyloplast stroma - Stromal localization of starch-biosynthetic enzymes and identification of an 81-kilodalton amyloplast stromal heat-shock cognate

被引:29
作者
Yu, Y [1 ]
Mu, HH [1 ]
Mu-Forster, C [1 ]
Wasserman, BP [1 ]
机构
[1] Rutgers State Univ, Cook Coll, New Jersey Agr Expt Stn, Dept Food Sci, New Brunswick, NJ 08901 USA
关键词
D O I
10.1104/pp.116.4.1451
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
In the developing endosperm of monocotyledonous plants, starch granules are synthesized and deposited within the amyloplast. A soluble stromal fraction was isolated from amyloplasts of immature maize (Zea mays L.) endosperm and analyzed for enzyme activities and polypeptide content. Specific activities of starch synthase and starch-branching enzyme (SBE), but not the cytosolic marker alcohol dehydrogenase, were strongly enhanced in soluble amyloplast stromal fractions relative to soluble extracts obtained from homogenized kernels or endosperms. Immunoblot analysis demonstrated that starch synthase I, SBEIIb, and sugary1, the putative starch-debranching enzyme, were each highly enriched in the amyloplast stroma, providing direct evidence for the localization of starch-biosynthetic enzymes within this compartment. Analysis of maize mutants shows the deficiency of the 85-kD SBEIIb polypeptide in the stroma of amylose extender cultivars and that the dull mutant lacks a >220-kD stromal polypeptide. The stromal fraction is distinguished by differential enrichment of a characteristic group of previously undocumented polypeptides. N-terminal sequence analysis revealed that an abundant 81-kD stromal polypeptide is a member of the Hsp70 family of stress-related proteins. Moreover, the 81-kD stromal polypeptide is strongly recognized by antibodies specific for an Hsp70 of the chloroplast stroma. These findings are discussed in light of implications for the correct folding and assembly of soluble, partially soluble, and granule-bound starch-biosynthetic enzymes during import into the amyloplast.
引用
收藏
页码:1451 / 1460
页数:10
相关论文
共 49 条
[1]   HSP70 PROTEINS, SIMILAR TO ESCHERICHIA-COLI DNAK, IN CHLOROPLASTS AND MITOCHONDRIA OF EUGLENA-GRACILIS [J].
AMIRSHAPIRA, D ;
LEUSTEK, T ;
DALIE, B ;
WEISSBACH, H ;
BROT, N .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1990, 87 (05) :1749-1752
[2]  
[Anonymous], 1991, OXFORD SURVEYS PLANT
[3]   MAJOR HEAT-SHOCK GENE OF DROSOPHILA AND THE ESCHERICHIA-COLI HEAT-INDUCIBLE DNAK GENE ARE HOMOLOGOUS [J].
BARDWELL, JCA ;
CRAIG, EA .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES, 1984, 81 (03) :848-852
[4]   Purification and characterization of chaperonin 60 and heat-shock protein 70 from chromoplasts of Narcissus pseudonarcissus - Involvement of heat-shock protein 70 in a soluble protein complex containing phytoene desaturase [J].
Bonk, M ;
Tadros, M ;
Vandekerckhove, J ;
AlBabili, S ;
Beyer, P .
PLANT PHYSIOLOGY, 1996, 111 (03) :931-939
[5]   Molecular chaperones and protein folding in plants [J].
Boston, RS ;
Viitanen, PV ;
Vierling, E .
PLANT MOLECULAR BIOLOGY, 1996, 32 (1-2) :191-222
[6]   EVIDENCE FOR INDEPENDENT GENETIC-CONTROL OF THE MULTIPLE FORMS OF MAIZE ENDOSPERM BRANCHING ENZYMES AND STARCH SYNTHASES [J].
BOYER, CD ;
PREISS, J .
PLANT PHYSIOLOGY, 1981, 67 (06) :1141-1145
[7]  
BRADFORD MM, 1976, ANAL BIOCHEM, V72, P248, DOI 10.1016/0003-2697(76)90527-3
[8]  
CAO HP, 1995, PHYSIOL PLANTARUM, V95, P176, DOI 10.1111/j.1399-3054.1995.tb00825.x
[9]   INTEGRATION AND ASSEMBLY OF PHOTOSYNTHETIC PROTEIN COMPLEXES IN CHLOROPLAST THYLAKOID MEMBRANES [J].
COHEN, Y ;
YALOVSKY, S ;
NECHUSHTAI, R .
BIOCHIMICA ET BIOPHYSICA ACTA-REVIEWS ON BIOMEMBRANES, 1995, 1241 (01) :1-30
[10]   SSC1, AN ESSENTIAL MEMBER OF THE YEAST HSP70 MULTIGENE FAMILY, ENCODES A MITOCHONDRIAL PROTEIN [J].
CRAIG, EA ;
KRAMER, J ;
SHILLING, J ;
WERNERWASHBURNE, M ;
HOLMES, S ;
KOSICSMITHERS, J ;
NICOLET, CM .
MOLECULAR AND CELLULAR BIOLOGY, 1989, 9 (07) :3000-3008