Distribution of the flavohaemoglobin, HMP, between periplasm and cytoplasm in Escherichia coli.
The subcellular distribution of the soluble flavohaemoglobin (HMP) of Escherichia coli has been determined. Cells over-expressing HMP from the cloned hmp gene on a multicopy plasmid were fractionated by osmotic shock and lysozyme treatment. Spectral analysis of subcellular fractions showed the CO-binding haemoprotein to be cytoplasmic. However, Western blotting using antibody raised to purified HMP revealed approximately 30% of the protein to be periplasmic in the over-expressing strain. Western analysis also revealed substantial levels of periplasmic HMP in a strain expressing only chromosomally encoded protein but none in an hmp mutant. The results are discussed in relation to protein function and the similar distribution reported for Vitreoscilla globin.
Vasudevan
S G
SG
Department of Molecular Sciences, James Cook University, Townsville, Australia.
Tang
P
P
Dixon
N E
NE
Poole
R K
RK
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D002248:Carbon Monoxide / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry; D004093:Dihydropteridine Reductase; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D005420:Flavoproteins / Q000032:analysis*; D005798:Genes, Bacterial; D005914:Globins / Q000737:chemistry; D006420:Hemeproteins / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000737:chemistry
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D005420:Flavoproteins; D006420:Hemeproteins; D002248:Carbon Monoxide; D005914:Globins; D004093:Dihydropteridine Reductase; C076538:hmp protein, E coli; D009247:NADH, NADPH Oxidoreductases