| 1. |
- Akselsson, Roland, et al.
(författare)
-
Aerosoler
- 1994
-
Bok (övrigt vetenskapligt/konstnärligt)
|
|
| 2. |
- Edvardsson, Mats, et al.
(författare)
-
Retorik och litteratur
- 1991
-
Ingår i: Samlaren. - Uppsala. - 0348-6133 .- 2002-3871. ; 112, s. 73-80
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Hansson, Göte, et al.
(författare)
-
Ethiopia - Away from Socialism
- 1993
-
Ingår i: Economic Crisis in Africa: Perspectives on Policy Responses. ; , s. 288-321
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 7. |
- Hansson, Mats, et al.
(författare)
-
Bacillus subtilis HemY is a peripheral membrane protein essential for protoheme IX synthesis which can oxidize coproporphyrinogen III and protoporphyrinogen IX
- 1994
-
Ingår i: Journal of Bacteriology. - 0021-9193. ; 176:19, s. 5962-5970
-
Tidskriftsartikel (refereegranskat)abstract
- The hemY gene of the Bacillus subtilis hemEHY operon is essential for protoheme IX biosynthesis. Two previously isolated hemY mutations were sequenced. Both mutations are deletions affecting the hemY reading frame, and they cause the accumulation of coproporphyrinogen III or coproporphyrin III in the growth medium and the accumulation of trace amounts of other porphyrinogens or porphyrins intracellularly. HemY was found to be a 53-kDa peripheral membrane-bound protein. In agreement with recent findings by Dailey et al. (J. Biol. Chem. 269:813-815, 1994) B. subtilis HemY protein synthesized in Escherichia coli oxidized coproporphyrinogen III and protoporphyrinogen IX to coproporphyrin and protoporphyrin, respectively. The protein is not a general porphyrinogen oxidase since it did not oxidize uroporphyrinogen III. The apparent specificity constant, kcat/Km, for HemY was found to be about 12-fold higher with coproporphyrinogen III as a substrate compared with protoporphyrinogen IX as a substrate. The protoporphyrinogen IX oxidase activity is consistent with the function of HemY in a late step of protoheme IX biosynthesis, i.e., HemY catalyzes the penultimate step of the pathway. However, the efficient coproporphyrinogen III to coproporphyrin oxidase activity is unexplained in the current view of protoheme IX biosynthesis.
|
|
| 8. |
- Hansson, Mats, et al.
(författare)
-
Cloning and characterization of the Bacillus subtilis hemEHY gene cluster, which encodes protoheme IX biosynthetic enzymes
- 1992
-
Ingår i: Journal of Bacteriology. - : American Society for Microbiology. - 0021-9193 .- 1098-5530. ; 174:24, s. 8081-8093
-
Tidskriftsartikel (refereegranskat)abstract
- Mutations that cause a block in a late step of the protoheme IX biosynthetic pathway, i.e., in a step after uroporphyrinogen III, map at 94 degrees on the Bacillus subtilis chromosomal genetic map. We have cloned and sequenced the hem genes at this location. The sequenced region contains six open reading frames: ponA, hemE, hemH, hemY, ORFA, and ORFB. The ponA gene product shows over 30% sequence identity to penicillin-binding proteins 1A of Escherichia coli, Streptococcus pneumoniae, and Streptococcus oralis and probably has a role in cell wall metabolism. The hemE gene was identified from amino acid sequence comparisons as encoding uroporphyrinogen III decarboxylase. The hemH gene was identified by enzyme activity analysis of the HemH protein expressed in E. coli. It encodes a water-soluble ferrochelatase which catalyzes the final step in protoheme IX synthesis, the insertion of ferrous iron into protoporphyrin IX. The function of the hemY gene product was not elucidated, but mutation analysis shows that it is required for a late step in protoheme IX synthesis. The hemY gene probably encodes an enzyme with coproporphyrinogen III oxidase or protoporphyrinogen IX oxidase activity or both of these activities. Inactivation of the ORFA and ORFB genes did not block protoheme IX synthesis. Preliminary evidence for a hemEHY mRNA was obtained, and a promoter region located in front of hemE was identified. From these combined results we conclude that the hemEHY gene cluster encodes enzymes for the synthesis of protoheme IX from uroporphyrinogen III and probably constitutes an operon.
|
|
| 9. |
|
|
| 10. |
- Hansson, Mats, et al.
(författare)
-
Heme b (protoheme IX) is a precursor of heme a and heme d in Bacillus subtilis
- 1993
-
Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 1574-6968 .- 0378-1097. ; 107:1, s. 121-126
-
Tidskriftsartikel (refereegranskat)abstract
- Bacillus subtilis can synthesise cytochromes containing a-, b-, c- and d-type heme. The biosynthetic pathways of these heme prosthetic groups were investigated by using strains blocked in uroporphyrinogen III synthesis from porphobilinogen or in heme b (protoheme IX) synthesis from uroporphyrinogen III. The results strongly suggest that heme a and heme d are both synthesised from heme b (protoheme IX). They also indicate that B. subtilis contains a novel ferrochelatase involved in the synthesis of siroheme
|
|
