Crystallization and preliminary X-ray diffraction studies of sortase A from Streptococcus pneumoniae

Anurag Misra, Tora Biswas, Sreetama Das, Uttara Marathe, Devinder Sehgal, Rajendra P. Roy, Ramakumar Suryanarayanarao

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Abstract

Sortases are cell-membrane-anchored cysteine transpeptidases that are essential for the assembly and anchoring of cell-surface adhesins in Gram-positive bacteria. Thus, they play critical roles in virulence, infection and colonization by pathogens. Sortases have been classified into four types based on their primary sequence and the target-protein motifs that they recognize. All Gram-positive bacteria express a class A housekeeping sortase (SrtA). Sortase A from Streptococcus pneumoniae (NP-358691) has been crystallized in two crystal forms. Diamond-shaped crystals of ΔN 59SrtA diffracted to 4.0 Å resolution and belonged to a tetragonal system with unit-cell parameters a = b = 122.8, c = 86.5 Å, α = β = γ = 90°, while rod-shaped crystals of ΔN 81SrtA diffracted to 2.91 Å resolution and belonged to the monoclinic space group P21 with unit-cell parameters a = 66.8, b = 103.47, c = 74.79 Å, α = γ = 90, β = 115.65°. The Matthews coefficient (V M = 2.77 Å 3 Da -1) with 56% solvent content suggested the presence of four molecules in the asymmetric unit for ΔN 81SrtA. Also, a multi-copy search using a monomer as a probe in the molecular-replacement method resulted in the successful location of four sortase molecules in the asymmetric unit, with statistics R = 41.61, R free = 46.44, correlation coefficient (CC) = 64.31, CCfree = 57.67.

Original languageEnglish (US)
Pages (from-to)1195-1198
Number of pages4
JournalActa Crystallographica Section F: Structural Biology and Crystallization Communications
Volume67
Issue number10
DOIs
StatePublished - Oct 1 2011

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Keywords

  • Streptococcus pneumoniae
  • cysteine transpeptidases
  • sortases

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Genetics
  • Condensed Matter Physics

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