TY - JOUR
T1 - Functional domains present in the mycobacterial hemagglutinin, HBHA
AU - Delogu, Giovanni
AU - 33182,
AU - FACOLTA', DI MEDICINA E CHIRURGIA "A.GEMELLI"
AU - ROMA - Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie
AU - Brennan, Mj
PY - 1999
Y1 - 1999
N2 - Identification and characterization of mycobacterial adhesins and complementary host receptors required for colonization and dissemination of mycobacteria in host tissues are needed for a more complete understanding of the pathogenesis of diseases caused by these bacteria and for the development of effective vaccines. Previous investigations have demonstrated that a 28-kDa heparin-binding mycobacterial surface protein, HBHA, can agglutinate erythrocytes and promote mycobacterial aggregation in vitro. In this study, further molecular and biochemical analysis of HBHA demonstrates that it has three functional domains: a transmembrane domain of 18 amino acids residing near the N terminus, a large domain of 81 amino acids consistent with an alpha-helical coiled-coil region, and a Lys-Pro-Ala-rich C-terminal domain that mediates binding to proteoglycans. Using His-tagged recombinant HBHA proteins and nickel chromatography we demonstrate that HBHA polypeptides which contain the coiled-coil region form multimers. This tendency to oligomerize may be responsible for the induction of mycobacterial aggregation since a truncated N-terminal HBHA fragment containing the coiled-coil domain promotes mycobacterial aggregation. Conversely, a truncated C-terminal HBHA fragment which contains Lys-Pro-Ala-rich repeats binds to the proteoglycan decorin. These results indicate that HBHA contains at least three distinct domains which facilitate intercalation into surface membranes, promote bacterium-bacterium interactions, and mediate the attachment to sulfated glycoconjugates found in host tissues.
AB - Identification and characterization of mycobacterial adhesins and complementary host receptors required for colonization and dissemination of mycobacteria in host tissues are needed for a more complete understanding of the pathogenesis of diseases caused by these bacteria and for the development of effective vaccines. Previous investigations have demonstrated that a 28-kDa heparin-binding mycobacterial surface protein, HBHA, can agglutinate erythrocytes and promote mycobacterial aggregation in vitro. In this study, further molecular and biochemical analysis of HBHA demonstrates that it has three functional domains: a transmembrane domain of 18 amino acids residing near the N terminus, a large domain of 81 amino acids consistent with an alpha-helical coiled-coil region, and a Lys-Pro-Ala-rich C-terminal domain that mediates binding to proteoglycans. Using His-tagged recombinant HBHA proteins and nickel chromatography we demonstrate that HBHA polypeptides which contain the coiled-coil region form multimers. This tendency to oligomerize may be responsible for the induction of mycobacterial aggregation since a truncated N-terminal HBHA fragment containing the coiled-coil domain promotes mycobacterial aggregation. Conversely, a truncated C-terminal HBHA fragment which contains Lys-Pro-Ala-rich repeats binds to the proteoglycan decorin. These results indicate that HBHA contains at least three distinct domains which facilitate intercalation into surface membranes, promote bacterium-bacterium interactions, and mediate the attachment to sulfated glycoconjugates found in host tissues.
KW - Amino Acid Sequence
KW - Electrophoresis, Polyacrylamide Gel
KW - Glycosaminoglycans
KW - Hemagglutinins
KW - Lectins
KW - Molecular Sequence Data
KW - Mycobacterium
KW - Protein Conformation
KW - Protein Structure, Secondary
KW - Structure-Activity Relationship
KW - Amino Acid Sequence
KW - Electrophoresis, Polyacrylamide Gel
KW - Glycosaminoglycans
KW - Hemagglutinins
KW - Lectins
KW - Molecular Sequence Data
KW - Mycobacterium
KW - Protein Conformation
KW - Protein Structure, Secondary
KW - Structure-Activity Relationship
UR - http://hdl.handle.net/10807/3581
M3 - Article
VL - 181
SP - 7464
EP - 7469
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
ER -