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A genomic clone encoding a cryptophyte phycoerythrin alpha-subunit. Evidence for three alpha-subunits and an
J Jenkins1, R G Hiller, J Speirs
1School of Biological Sciences, Macquarie University, N.S.W., Australia.
FEBS Letters
|October 29, 1990
Summary
Researchers identified multiple genes for phycoerythrin alpha-subunits in Chroomonas (Cryptophyceae) using genomic library construction and DNA sequencing. This suggests a complex genetic basis for this photosynthetic pigment protein.
Area of Science:
- * Molecular biology
- * Biochemistry
- * Phycology
Background:
- * Phycoerythrin is a crucial accessory pigment in Cryptophyceae algae, vital for photosynthesis.
- * Understanding the genetic basis of phycoerythrin subunits is key to elucidating its structure and function.
Purpose of the Study:
- * To construct and screen a genomic library of Chroomonas DNA.
- * To isolate and sequence genes encoding phycoerythrin alpha-subunits.
- * To investigate the genetic diversity of alpha-subunits within Chroomonas.
Main Methods:
- * Construction of a Chroomonas genomic DNA library in lambda EMBL4.
- * Hybridization screening using a synthetic oligomer probe.
- * DNA sequencing of isolated clones.
- * Partial protein sequencing of alpha-subunits via Edman degradation.
Main Results:
- * A clone containing a phycoerythrin alpha-subunit gene was successfully isolated and sequenced.
- * The DNA-derived sequence of the alpha-subunit gene is GC-rich.
- * Partial protein sequencing revealed discrepancies with the DNA sequence, indicating at least three distinct alpha-subunit genes.
- * An N-terminal extension in the deduced protein sequence suggests a thylakoid-lumen targeting signal.
Conclusions:
- * Chroomonas possesses multiple genes for phycoerythrin alpha-subunits.
- * The identified gene encodes an N-terminal extension potentially involved in protein localization.
- * Discrepancies between DNA and protein sequences highlight the complexity of phycoerythrin gene expression.