title: NADP-malic enzyme and Hsp70: co-purification of both proteins and modification of NADP-malic enzyme properties by association with Hsp70.
abstract: Different preparations of antibodies against 62 kDa NADP-malic enzyme (NADP-ME) from purified maize leaves cross-react with a 72 kDa protein from diverse tissues in many species. A 72 kDa protein, suggested to be a non-photosynthetic NADP-ME, has been purified from several plant species. However, to date, a cDNA coding for this putative 72 kDa NADP-ME has not been isolated. The screening of maize and tobacco leaf expression libraries using antibodies against purified 62 kDa NADP-ME allowed the identification of a heat shock protein (Hsp70). In addition, tandem mass spectrometry (MS/MS) studies indicate that along with NADP-ME, a 72 kDa protein, identified as an Hsp70 and reacting with the antibodies, is also purified from maize roots. On the other hand, the screening of a maize root cDNA library revealed the existence of a cDNA that encodes a mature 66 kDa NADP-ME. These results suggest that the 72 kDa protein is not actually an NADP-ME but in fact an Hsp70, at least in maize and tobacco. Probably, NADP-ME-Hsp70 association, taking place at least when preparing crude extracts, can lead to a co-purification of the proteins and can thus explain the cross-reaction of the antibodies. In the present work, we analyse and discuss a probable interaction of NADP-ME with Hsp70.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 531, Rosario (2000), Argentina.
authors.forename: María V
authors.initials: MV
authors.lastname: Lara
authors.forename: María F
authors.initials: MF
authors.lastname: Drincovich
authors.forename: Gabriela L
authors.initials: GL
authors.lastname: Müller
authors.forename: Verónica G
authors.initials: VG
authors.lastname: Maurino
authors.forename: Carlos S
authors.initials: CS
authors.lastname: Andreo
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003429:Cross Reactions; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004795:Enzyme Stability; D015723:Gene Library; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000235:genetics / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D018840:HSP70 Heat-Shock Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)