The hemX gene of the Bacillus subtilis hemAXCDBL operon encodes a membrane protein, negatively affecting the steady-state cellular concentration of HemA (glutamyl-tRNA reductase)
The Bacillus subtilis hemAXCDBL operon encodes enzymes for the biosynthesis of uroporphyrinogen III from glutamyl-tRNA. The function of the hemX gene product was studied in this work. The deduced amino acid sequence suggests HemX to be an integral 32 kDa membrane protein. This was confirmed by experiments using Escherichia coli minicells and hemX-phoA gene fusions. Deletion of the hemX gene from the Bacillus subtilis chromosome demonstrated that this gene is not required for haem synthesis. However, the deletion strain was found to overexpress the hemA gene product, glutamyl-tRNA reductase. A combination of results obtained with B. subtilis hemA and hemX in Escherichia coli and Bacillus subtilis shows that HemX negatively affects the steady-state cellular concentration of HemA protein. The mechanism by which HemX affects the HemA concentration is unclear.
BealeS.I.,
WeinsteinJ.D. Tetrapyrrole metabolism in photosynthetic organisms. In Biosynthesis of Heme and Chlorophylls1990 Edited by
DaileyH.A.
New York: McGraw-Hill; pp 287–391
ChangA.C.Y.,
CohenS.N. Construction and characterization of amplifiable multicopy DNA cloning vehicles derived from the P15A cryptic miniplasmid. J Bacteriol1978; 134:1141–1166
FridénH.,
HederstedtL. Role of His residues in Bacillus subtilis cytochrome 558 for haem binding and assembly of succinate: quinone oxidoreductase (complex II). Mol Microbiol1990; 4:1045–1056
GöttP.,
BoosW. The transmembrane topology of the sn-glycerol-3-phosphate permease of Escherichia coli analysed by phoA and lacZ protein fusions. Mol Microbiol1988; 2:655–663
HanssonM.,
HederstedtL. Cloning and characterization of the Bacillus subtilis hemEHY gene cluster which encodes protoheme IX biosynthetic enzymes. J Bacteriol1992; 174:8081–8093
HanssonM.,
RutbergL.,
SchröderI.,
HederstedtL. The Bacillus subtilis hemAXCDBE gene cluster, which encodes enzymes of the biosynthetic pathway from glutamate to uroporphyrino-genlll. J Bacteriol1991; 173:2590–2599
JahnD.,
O’NeillG.P.,
VerkampE.,
SbllD. Glutamate tRNA: involvement in protein synthesis and aminolevulinate formation in Chlamydomonas reinhardii. Riant Physiol Biochem1992; 30:245–253
NevilleD.M.Jr Molecular weight determination of protein-dodecyl-sulphate complexes by gel electrophoresis in a discontinuous buffer system. J Biol Chem1971; 246:6328–6334
Oh-hamaT.,
StolowichN.J.,
ScottA.I. 5-Aminolevulinic acid formation from glutamate via the C5 pathway in Clostridium thermoaceticum. FEBS Eett1988; 228:89–93
OwenP. Immunology of the bacterial membrane. In Organisation of the Procaryotic Cell Membranes1981 Edited by
GhoshB.K.
Boca Raton, FL: CRC Press; pp 73–164
PardeeA.B.,
JacobF.,
MonodJ. The genetic control and cytoplasmic expression of “inducibility” in the synthesis of β-galactosidase by E coli. J Mol Biol1959; 1:165–178
PetricekM.,
RutbergL.,
SchröderI.,
HederstedtL. Cloning and characterization of the hemA region of the Bacillus subtilis chromosome. J Bacteriol1990; 172:2250–2258
SchröderI.,
HederstedtL.,
KannangaraC.G.,
GoughS.P. Glutamyl -tRNA reductase activity in Bacillus subtilis is dependent on the hemA gene product. Biochem J1992; 281:843–850
ShinozakiK.
and others The complete nucleotide sequence of the tobacco chloroplast genome: its gene organization and expression. EMBO J1986; 5:2043–2049
Von HeijneG.,
AbrahamsenL. Species-specific variation in signal peptide design. Implications for protein secretion in foreign hosts.. FEBS Lett1989; 244:439–446
Yanisch-PerronC.,
VieiraJ.,
MessingJ. Improved Ml 3 phage cloning vectors and host strains: nucleotide sequences of the M13mpl8 and pUC19 vectors. Gene1985; 33:103–119
The hemX gene of the Bacillus subtilis hemAXCDBL operon encodes a membrane protein, negatively affecting the steady-state cellular concentration of HemA (glutamyl-tRNA reductase)