EC Number   |
Natural Substrates |
|---|
   3.4.22.B64 | major pilin protein BcpA precursor + H2O |
BcpA cleavage by SrtD leads to the assembly of pili, fibrous structures formed by intermolecular amide bonds between the C-terminal threonine of cleaved sorting signals (Thr522) and the conserved lysine residue of the YPKN motif (Lys162). The acyl enzyme of SrtD can be viewed as an assembly platform for the capture of polymerized pili via thioester linked intermediates with the C-terminal threonine of the last pilin subunit |
| 3.4.22.B64 | more |
Corynebacterium diphtheriae SpaA pili are composed of three pilin subunits, SpaA, SpaB and SpaC. SpaA, the major pilin protein, is distributed uniformly along the pilus shaft, whereas SpaB is observed at regular intervals, and SpaC seems to be positioned at the pilus tip. Deletion of sortase gene srtD does not affected SpaA pilus assembly, polymerization of SpaA precursor into high-molecular-weight species or polymerization of SpaB into SpaBHMW complexes. When the main fimbrial subunit of Actinomyces naeslundii type I fimbriae, FimA, is expressed in Corynebacterium diphtheriae, FimA is polymerized to form short fibres. Although Corynebacterium diphtheriae does not depend on other actinomycetal genes for FimA polymerization, this process involves the pilin motif and the sorting signal of FimA as well as corynebacterial sortase D |
| 3.4.22.B64 | more |
of the three genes for structural subunits, rrgB encodes the major pilin, while rrgA and rrgC encode ancillary pilin subunits decorating the pilus shaft and tip. Deletion of all three pilus associated sortase genes, srtB, srtC and srtD, completely prevents pilus biogenesis. SrtD does not act as a pilus subunit polymerase, but instead is required for wild-type focal presentation of the pilus at the cell surface |
| 3.4.22.B64 | pilin protein BcpA + H2O |
Bacillus cereus and other Gram-positive bacteria elaborate pili via a sortase D-catalyzed transpeptidation mechanism from major and minor pilin precursor substrates. After cleavage of the LPXTG sorting signal of the major pilin, BcpA, sortase D forms an amide bond between the C-terminal threonine and the amino group of lysine within the YPKN motif of another BcpA subunit. The IPNTG sorting signal of BcpB, the minor pilin, is cleaved by sortase D but not by sortase A. The C-terminal threonine of BcpB is amide-linked to the YPKN motif of BcpA, thereby positioning BcpB at the tip of pili |
| 3.4.22.B64 | pilin protein BcpA + H2O |
the major pilin protein BcpA is cleaved between the threonine and the glycine of its C-terminal LPXTG motif sorting signal. The resulting acyl enzyme intermediate is relieved by the nucleophilic attack of the side-chain amino group of lysine within the YPKN motif of another BcpA subunit. Cell wall anchoring of assembled BcpA pili requires sortase A, which also cleaves the LPXTG sorting signal of BcpA between its threonine and glycine residues |
| 3.4.22.B64 | pilin protein BcpB + H2O |
Bacillus cereus and other Gram-positive bacteria elaborate pili via a sortase D-catalyzed transpeptidation mechanism from major and minor pilin precursor substrates. After cleavage of the LPXTG sorting signal of the major pilin, BcpA, sortase D forms an amide bond between the C-terminal threonine and the amino group of lysine within the YPKN motif of another BcpA subunit. The IPNTG sorting signal of BcpB, the minor pilin, is cleaved by sortase D but not by sortase A. The C-terminal threonine of BcpB is amide-linked to the YPKN motif of BcpA, thereby positioning BcpB at the tip of pili |
