Journal article
Nodulin-24 follows a novel pathway for integration into the peribacteroid membrane in soybean root nodules
The Journal of biological chemistry, Vol.269(9), pp.6598-6602
03/04/1994
Handle:
https://hdl.handle.net/2376/108720
PMID: 8120012
Abstract
Nodulin-24 is a nodule-specific protein of the peribacteroid membrane (PBM) in soybean. It has an apparent molecular mass of 33 kDa while its full-length cDNA encodes a polypeptide of only 24 kDa. In vitro transcription of nodulin-24 cDNA followed by translation resulted in a peptide translocated into microsomal membranes with cleavage of a signal sequence. The cleavage site of the signal sequence in nodulin-24 was determined to be between Ala (A25) and Arg (R26) by microsequencing of the [3H]leucine-labeled processed peptide. Fusion of the signal sequence of nodulin-24 with the beta-glucuronidase peptide prevented co-translational cleavage of the signal sequence although the translocation of the fused protein into microsomes occurred co-translationally. Trypsin treatment of membrane-translocated nodulin-24 did not result in any alteration in size suggesting that the newly synthesized peptide is fully protected in the membrane vesicle. Fusion of nodulin-24 with beta-glucuronidase also showed no change in size following trypsin treatment, suggesting that nodulin-24 has no membrane-spanning region. In addition, in vitro synthesized nodulin-24 was present in the supernatant fraction after sonication of microsomal membranes. Mature nodulin-24, on the other hand, is not solubilized from PBM by sodium carbonate (pH 11) or EGTA and is soluble only in detergent. These data suggest that nodulin-24 is synthesized as a lumenal protein in the endoplasmic reticulum and post-translationally attached to the membranes en route to the PBM. This processing results in a significant increase in the apparent molecular mass of nodulin-24 which may be due to the attachment of membrane lipids as this protein shares characteristics with membrane lipoproteins of many pathogenic bacteria.
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Details
- Title
- Nodulin-24 follows a novel pathway for integration into the peribacteroid membrane in soybean root nodules
- Creators
- C I Cheon - Department of Molecular Genetics, Ohio State University, Columbus 43210Z HongD P Verma
- Publication Details
- The Journal of biological chemistry, Vol.269(9), pp.6598-6602
- Academic Unit
- Center for Reproductive Biology
- Publisher
- United States
- Identifiers
- 99900547735901842
- Language
- English
- Resource Type
- Journal article