Effect of iron regulation on expression and hemin-binding function of outer-sheath proteins from Treponema denticola.
The effect of the iron-chelating compounds EDDA and BPD on polypeptide regulation in the putative oral pathogen Treponema denticola was studied. SDS-PAGE analysis of the T. denticola strains grown in the presence of EDDA or BPD, i.e. iron-limiting environmental conditions, revealed the expression of 44 and 43 kDa polypeptides in the outer sheath, a 73 kDa polypeptide in the cell membrane, and a 16 kDa polypeptide in the soluble cell fraction. The hemin-binding activity of purified outer sheaths from T. denticola TD-4 grown in the presence of 6.4 mM EDDA was significantly greater than that observed in control (absence of EDDA) outer sheaths. Both activities were inhibited by proteinase K. SDS-PAGE, LDS-PAGE and TMBZ staining revealed the 44 and 43 kDa outer-sheath polypeptides to be expressed by T. denticola strains GM-1. MS-25, ATCC 33520 and ATCC 33404 (TD-4), strains which possessed strong hemin-binding activity. The 44 kDa hemin-binding polypeptide was purified by 1% CHAPS solubilization, HPLC, and SDS-preparative electrophoresis. N'-terminal sequence analysis indicated the purified 44 kDa polypeptide to belong to a new, undescribed group of polypeptides possessing hemin-binding activity.
Chu
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University of Texas Health Science Center at San Antonio 78284.
Song
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M
Holt
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SC
D015082:2,2'-Dipyridyl / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology*; D003470:Culture Media / Q000494:pharmacology; D004492:Edetic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D006427:Hemin / Q000378:metabolism*; D007501:Iron / Q000494:pharmacology*; D033862:Iron-Binding Proteins; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000187:drug effects; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D033863:Transferrin-Binding Proteins; D014208:Treponema / Q000187:drug effects* / Q000235:genetics
D000906:Antibodies; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D002614:Chelating Agents; D003470:Culture Media; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D033862:Iron-Binding Proteins; D033863:Transferrin-Binding Proteins; D015082:2,2'-Dipyridyl; C026058:EDDA; D006427:Hemin; D004492:Edetic Acid; D007501:Iron