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The truncated hemoglobin from Mycobacterium leprae.
- Source :
-
Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2002 Jun 28; Vol. 294 (5), pp. 1064-70. - Publication Year :
- 2002
-
Abstract
- Truncated hemoglobins (trHb's) form a family of low molecular weight O2 binding hemoproteins distributed in eubacteria, protozoa, and plants. TrHb's branch in a distinct clade within the hemoglobin (Hb) superfamily. A unique globin gene has recently been identified from the complete genome sequence of Mycobacterium leprae that is predicted to encode a trHb (M. leprae trHbO). Sequence comparison and modelling considerations indicate that monomeric M. leprae trHbO has structural features typical of trHb's, such as 20-40 fewer residues than conventional globin chains, Gly-based sequence consensus motifs, likely assembling into a 2-on-2 alpha-helical sandwich fold, and hydrophobic residues recognized to build up the protein matrix ligand diffusion tunnel. The ferrous heme iron atom of deoxygenated M. leprae trHbO appears to be hexacoordinated, like in Arabidopsis thaliana trHbO-3 (A. thaliana trHbO-3). Accordingly, the value of the second-order rate constant for M. leprae trHbO carbonylation (7.3 x 10(3) M(-1) s(-1)) is similar to that observed for A. thaliana trHbO-3 (1.4 x 10(4) M(-1) s(-1)) and turns out to be lower than that reported for carbon monoxide binding to pentacoordinated Mycobacterium tuberculosis trHbN (6.7 x 10(6) M(-1) s(-1)). The lower reactivity of M. leprae trHbO as compared to M. tuberculosis trHbN might be related to the higher susceptibility of the leprosy bacillus to toxic nitrogen and oxygen species produced by phagocytic cells.
- Subjects :
- Amino Acid Sequence
Bacterial Proteins chemistry
Base Sequence
Cloning, Molecular
Hemoglobins chemistry
Ligands
Models, Molecular
Molecular Sequence Data
Recombinant Proteins isolation & purification
Recombinant Proteins metabolism
Sequence Homology, Amino Acid
Spectrophotometry
Truncated Hemoglobins
Bacterial Proteins genetics
Bacterial Proteins metabolism
Hemoglobins genetics
Hemoglobins metabolism
Mycobacterium leprae
Subjects
Details
- Language :
- English
- ISSN :
- 0006-291X
- Volume :
- 294
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Biochemical and biophysical research communications
- Publication Type :
- Academic Journal
- Accession number :
- 12074585
- Full Text :
- https://doi.org/10.1016/S0006-291X(02)00593-4