The CD27L and CTP1L Endolysins Targeting Clostridia Contain a Built-in Trigger and Release Factor
نویسندگان
چکیده
The bacteriophage ΦCD27 is capable of lysing Clostridium difficile, a pathogenic bacterium that is a major cause for nosocomial infection. A recombinant CD27L endolysin lyses C. difficile in vitro, and represents a promising alternative as a bactericide. To better understand the lysis mechanism, we have determined the crystal structure of an autoproteolytic fragment of the CD27L endolysin. The structure covers the C-terminal domain of the endolysin, and represents a novel fold that is identified in a number of lysins that target Clostridia bacteria. The structure indicates endolysin cleavage occurs at the stem of the linker connecting the catalytic domain with the C-terminal domain. We also solved the crystal structure of the C-terminal domain of a slow cleaving mutant of the CTP1L endolysin that targets C. tyrobutyricum. Two distinct dimerization modes are observed in the crystal structures for both endolysins, despite a sequence identity of only 22% between the domains. The dimers are validated to be present for the full length protein in solution by right angle light scattering, small angle X-ray scattering and cross-linking experiments using the cross-linking amino acid p-benzoyl-L-phenylalanine (pBpa). Mutagenesis on residues contributing to the dimer interfaces indicates that there is a link between the dimerization modes and the autocleavage mechanism. We show that for the CTP1L endolysin, there is a reduction in lysis efficiency that is proportional to the cleavage efficiency. We propose a model for endolysin triggering, where the extended dimer presents the inactive state, and a switch to the side-by-side dimer triggers the cleavage of the C-terminal domain. This leads to the release of the catalytic portion of the endolysin, enabling the efficient digestion of the bacterial cell wall.
منابع مشابه
Structure-based modification of a Clostridium difficile-targeting endolysin affects activity and host range.
Endolysin CD27L causes cell lysis of the pathogen Clostridium difficile, a major cause of nosocomial infection. We report a structural and functional analysis of the catalytic activity of CD27L against C. difficile and other bacterial strains. We show that truncation of the endolysin to the N-terminal domain, CD27L1-179, gave an increased lytic activity against cells of C. difficile, while the ...
متن کاملComparison of Positional Release Technique with and without strain-counter strain technique on the pain, neck range of motion in men with active trigger points in upper trapezius muscle
Aims and background: Trigger points are sensitive points in the skeletal muscle and neck muscles that cause referral pain, decrease the range of motion and muscle soreness. Therefore, the purpose of this study was to compare the effect of the Positional Release Technique with and without strain-counter strain technique on the pain, neck range of motion in men with active trigger points in uppe...
متن کاملPercutaneous Release of Trigger Fingers: Comparing Multiple Digits with Single Digit Involvement
Background: To evaluate safety and efficacy of percutaneous release of trigger finger in multiple digits involvement in comparison with single digit involvement. Method: A number of 100 patients (131 fingers) were treated by percutaneous release and divided into two groups: single digit (group A) and multiple digits (group B). They were followed up for one year. Success rate, pain, complic...
متن کاملCongenital Bilateral Multiple Trigger Fingers in A 5-Year-Old Child
Paediatric bilateral multiple trigger fingers are extremely rare. The underlying etiopathogenesis and hence the surgical principles of management of trigger finger in children are different from those of pediatric trigger thumb and adult trigger finger. In this paper, we report the case of a 5 year old girl with congenital trigger digits involving the middle, ring and little fingers of both han...
متن کاملIsolation and identification of Clostridium septicum from sheep-dung
To study the existence of Clostridium septicum as probable agent associated with currently occurrence of black quarter in Urmia area, sheep-dung samples were collected. The bacteriological examinations on suspicious gram positive anaerobic spore-bearing bacilli which are in Clostridia genus include isolation and biochemical identification were performed. The results showed 28 different types ...
متن کامل