The multifunctional protein OBF1 is phosphorylated at serine and threonine residues in Saccharamyces cerevisiae

Journal Article · Wed May 15 04:00:00 EDT 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.10.4089· OSTI ID:6100772

Francesconi, S C; Eisenberg, S ^[1]

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1. Univ. of Connecticut Health Center, Farmington (United States)

The authors have purified a DNA replication enhancer-binding protein, OFB1, from yeast cells grown in a medium containing {sup 32}P-labeled orthophosphate. The purified {sup 32}P-labeled protein comigrated on polyacrylamide gels with OFB1 bands identified by immunoblotting with anti-OBF1 antibodies. Furthermore, trypsin treatment of the {sup 32}P-labeled OBF1 revealed several phosphorylated peptides, suggesting that OBF1 is multiply phosphorylated in vivo. Incubation of phosphorylated peptides with calf intestinal phosphatase liberated the radiolabel as free phosphate, indicating a phosphoester linkage. Acid hydrolysis of the tryptic peptides revealed {sup 32}P label comigrating with phosphoserine; some of it, however, was also identified as phosphothreonine. Using anti-OBF1 antibodies, we cloned the OFB1 gene from a {lambda}gt11 yeast expression library. The DNA sequence of the isolated gene and its overexpression in yeast indicated that OFB1 is identical to ABF-I and BAF1 proteins, believed to have a role in transcriptional repression and activation. Therefore, they suggest that OBF1 is a multifunctional protein, acting in transcription and replication, and that these activities are regulated by phosphorylation.

• OSTI ID: 6100772
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States) Vol. 88:10; ISSN PNASA; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID HYDROLYSIS
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DNA REPLICATION
DNA SEQUENCING
EUMYCOTA
FUNGI
GENES
HYDROLYSIS
HYDROXY ACIDS
ISOTOPES
LIGHT NUCLEI
LYSIS
MICROORGANISMS
NUCLEI
NUCLEIC ACID REPLICATION
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PLANTS
PROTEINS
RADIOISOTOPES
SACCHAROMYCES
SACCHAROMYCES CEREVISIAE
SERINE
SOLVOLYSIS
STRUCTURAL CHEMICAL ANALYSIS
THREONINE
TRANSCRIPTION
YEASTS