Solution structure of the major (Spy0128) and minor (Spy0125 and Spy0130) pili subunits from Streptococcus pyogenes
- 238 Downloads
Adhesion of the serotype M1 Streptococcus pyogenes strain SF370 to human tonsil explants and cultured keratinocytes requires extended polymeric surface structures called pili. In this important human pathogen, pili are assembled from three protein subunits: Spy0125, Spy0128 and Spy0130 through the action of sortase enzymes. For this study, the structural properties of these pili proteins have been investigated in solution. Spy0125 and Spy0128 display characteristics of globular, folded proteins. Circular dichroism suggests a largely β-sheet composition for Spy0128 and Spy0125; Spy0130 appears to contain little secondary structure. Each of the proteins adopts a monodisperse, monomeric state in solution as assessed by analytical ultracentrifugation. Further, small-angle X-ray scattering curves for Spy0125, Spy0128 and Spy0130 suggest each protein adopts an elongated shape, likely comprised of two domains, with similar maximal dimensions. Based on the scattering data, dummy atom models of each of the pili subunits have been reconstructed ab initio. This study provides the first insights into the structure of Streptococcus pyogenes minor pili subunits, and possible implications for protein function are discussed.
KeywordsPili subunits Circular dichroism Analytical ultracentrifugation Small-angle X-ray scattering Dummy atom model Structural disorder
This work was supported, in part, by MRC project grant G0400849 (to MAK) and a Royal Society University Research Fellowship to Mark J. Banfield. Jonathan A. Pointon is supported by a studentship from the Medical Research Council (MRC), UK. Alexandra S. Solovyova and Mark J. Banfield are grateful to Newcastle University for funding. The authors thank the Daresbury-SRS (UK) and the EMBL-Hamburg Outstation (Germany) for the provision of beamtime and the expert assistance of beamline staff and software developers during data acquisition and data treatment [specifically Günter Grossmann (SRS), Dmitri Svergun and Peter Konarev (EMBL-DESY)].
- Boulin C, Kempf R, Koch MHJ, Mc Laughlin SM (1986) Data appraisal, evaluation and display for synchrotron radiation experiments: hardware and software. Nucl Instrum Methods A249:399–407Google Scholar
- Durchschlag H (1986) Specific volumes of biological macromolecules and some other molecules of biological interest. In: Hinz H-J (ed) Thermodynamic data for biochemistry and biotechnology. Springer, Berlin, pp 45–128Google Scholar
- Feigin LA, Svergun DI (1987) Structure analysis by small-angle X-ray and neutron scattering. Plenum Press, New YorkGoogle Scholar
- Lamm O (1929) Die Differentialgleichung der Ultrazentrifugierung. Ark Mater Astron Fys 21B:1–4Google Scholar
- Laue TM, Shah BD, Ridgeway TM, Pelletier S (1992) Computer-aided interpretation of analytical sedimentation data for proteins. In: Analytical ultracentrifugation in biochemistry and polymer science. Redwood Press Ltd, Melksham, pp 90–125Google Scholar
- Longhi S, Receveur-Bréchot V, Karlin D, Johansson K, Darbon H, Bhella D, Yeo R, Finet S, Canard B (2003) The C-terminal domain of the measles virus nucleoprotein is intrinsically disordered and folds upon binding to the C-terminal moiety of the phosphoprotein. J Biol Chem 278:18638–18648. doi: 10.1074/jbc.M300518200 CrossRefPubMedGoogle Scholar
- Proft T, Baker EN (2008) Pili in Gram-negative and Gram-positive bacteria - structure, assembly and their role in disease. Cell Mol Life Sci. doi: 10.1007/s00018-008-8477-4:-8
- Romero P, Obradovic Z, Li X, Garner EC, Brown CJ, Dunker AK (2001) Sequence complexity of disordered protein. Proteins 42:38–48. doi: 10.1002/1097-0134(20010101)42:1<38::AID-PROT50>3.0.CO;2-3 CrossRefPubMedGoogle Scholar