Stromal Processing Peptidase Binds Transit Peptides and Initiates Their Atp-Dependent Turnover in Chloroplasts

Autor: Gayle K. Lamppa, Stefan Richter
Rok vydání: 1999
Předmět:
0106 biological sciences
Chloroplasts
Mitochondrial processing peptidase
Metallopeptidase
Proteolysis
Molecular Sequence Data
metallopeptidase
transit peptide
Plasma protein binding
Protein Sorting Signals
Sodium Chloride
Biology
01 natural sciences
03 medical and health sciences
chemistry.chemical_compound
stromal processing peptidase
Adenosine Triphosphate
chloroplast
Plant Cells
Transit Peptide
medicine
Amino Acid Sequence
Protein Precursors
Binding site
Peptide sequence
Chelating Agents
Plant Proteins
030304 developmental biology
0303 health sciences
Binding Sites
medicine.diagnostic_test
Temperature
Metalloendopeptidases
Biological Transport
Cell Biology
Hydrogen-Ion Concentration
Plants
Recombinant Proteins
chemistry
Biochemistry
Ethylmaleimide
protein degradation
Original Article
Protein Processing
Post-Translational
Adenosine triphosphate
Phenanthrolines
Protein Binding
010606 plant biology & botany
Zdroj: The Journal of Cell Biology
ISSN: 1540-8140
0021-9525
DOI: 10.1083/jcb.147.1.33
Popis: A stromal processing peptidase (SPP) cleaves a broad range of precursors targeted to the chloroplast, yielding proteins for numerous biosynthetic pathways in different compartments. SPP contains a signature zinc-binding motif, His-X-X-Glu-His, that places it in a metallopeptidase family which includes the mitochondrial processing peptidase. Here, we have investigated the mechanism of cleavage by SPP, a late, yet key event in the import pathway. Recombinant SPP removed the transit peptide from a variety of precursors in a single endoproteolytic step. Whereas the mature protein was immediately released, the transit peptide remained bound to SPP. SPP converted the transit peptide to a subfragment form that it no longer recognized. We conclude that SPP contains a specific binding site for the transit peptide and additional proteolysis by SPP triggers its release. A stable interaction between SPP and an intact transit peptide was directly demonstrated using a newly developed binding assay. Unlike recombinant SPP, a chloroplast extract rapidly degraded both the transit peptide and subfragment. A new degradative activity, distinguishable from SPP, was identified that is ATP- and metal-dependent. Our results indicate a regulated sequence of events as SPP functions during precursor import, and demonstrate a previously unrecognized ATP-requirement for transit peptide turnover.
Databáze: OpenAIRE
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