3G66

The crystal structure of Streptococcus pneumoniae Sortase C provides novel insights into catalysis as well as pilin substrate specificity

Summary for 3G66

• Entry DOI: 10.2210/pdb3g66/pdb
• Related: 3G69
• Descriptor: Sortase C, 2-(N-MORPHOLINO)-ETHANESULFONIC ACID (3 entities in total)
• Functional Keywords: sortase, pilus, s. pneumoniae, transferase
• Biological source: Streptococcus pneumoniae
• Total number of polymer chains: 2
• Total formula weight: 48475.06

Authors

Neiers, F.,Madhurantakam, C.,Falker, S.,Manzano, C.,Dessen, A.,Normark, S.,Henriques-Normark, B.,Achour, A. (deposition date: 2009-02-06, release date: 2009-09-01, Last modification date: 2023-09-06)

Primary citation

Neiers, F.,Madhurantakam, C.,Falker, S.,Manzano, C.,Dessen, A.,Normark, S.,Henriques-Normark, B.,Achour, A.
Two crystal structures of pneumococcal pilus sortase C provide novel insights into catalysis and substrate specificity.
J.Mol.Biol., 393:704-716, 2009

PubMed Abstract: The respiratory tract pathogen Streptococcus pneumoniae is a primary cause of morbidity and mortality worldwide. Pili enhance initial adhesion as well as the capacity of pneumococci to cause pneumonia and bacteremia. Pilus-associated sortases (SrtB, SrtC, and SrtD) are involved in the biogenesis of pneumococcal pili, composed of repeating units of RrgB that create the stalk to which the RrgA adhesin and the preferential pilus tip subunit RrgC are covalently associated. Using single sortase-expressing strains, we demonstrate that both pilin-polymerizing sortases SrtB and SrtC can covalently link pili to the peptidoglycan cell wall, a property shared with the non-pilus-polymerizing enzyme SrtD and the housekeeping sortase SrtA. Comparative analysis of the crystal structures of S. pneumoniae SrtC and SrtB revealed structural differences explaining the incapacity of SrtC, but not of SrtB, to incorporate RrgC into the pilus. Accordingly, site-directed mutagenesis of Thr(160) in SrtB to an arginine as in SrtC (Arg(160)) partially converted its substrate specificity into that of SrtC. Solving two crystal structures for SrtC suggests that an opening of a flexible lid and a concomitant cysteine rotation are important for catalysis and the activation of the catalytic cysteine of pilus-associated sortases.

PubMed: 19729023
DOI: 10.1016/j.jmb.2009.08.058

Experimental method

X-RAY DIFFRACTION (1.7 Å)