Identification of Four Families of Peptidoglycan Lytic Transglycosylases

Blackburn, Neil T.; Clarke, Anthony J.

doi:10.1007/s002390010136

Cited by 127 publications

(182 citation statements)

References 18 publications

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“…Presumably, the lack of prior identification of this activity in Gram-negative bacteria together with knowledge of its structure possessing a lysozyme-fold led to is incorrect assignment by some as a muramidase. Identification of enzyme specificity became complicated with observations that FlgJ shares sequence identity with family 1E LTs, enzymes that also possess the lysozyme-fold and represent the major class of autolysin with glycolytic activity in Gram-negative bacteria (15,41). Given this, the misassignment of FlgJ as an LT is understandable.…”

Section: Discussionmentioning

confidence: 99%

The Essential Protein for Bacterial Flagella Formation FlgJ Functions as a β-N-Acetylglucosaminidase

Herlihey

Moynihan

Clarke

2014

Journal of Biological Chemistry

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Background: FlgJ is required for flagella formation in Salmonella enterica. Results: The lytic activity of FlgJ was determined to be that of a ␤-N-acetylglucosaminidase using a novel assay. Conclusion: FlgJ is a hydrolase and not a lytic transglycosylase. Significance: This information is essential for the search and rational design of inhibitors that may serve as leads to a new class of antibiotics.

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Section: Discussionmentioning

confidence: 99%

The Essential Protein for Bacterial Flagella Formation FlgJ Functions as a β-N-Acetylglucosaminidase

Herlihey

Moynihan

Clarke

2014

Journal of Biological Chemistry

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“…A total of 11 LTs, MltA (PA1222), MltB (PA4444), MltD (PA1812), MltF (PA3764), MltF2 (PA2865), MltG (PA2963), Slt (PA3020), SltB2 (PA1171), SltH/SltB3 (PA3992) and RlpA (PA4000) were reported in P. aeruginosa [95][96][97][98][99]. A few studies separately enumerate the enzymatic activities of all the LTs [97,99,100].…”

Section: Lytic Transglycosylases (Lts)mentioning

confidence: 99%

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Dhar

Kumari

Balasubramanian

et al. 2018

Journal of Medical Microbiology

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The bacterial cell-wall that forms a protective layer over the inner membrane is called the murein sacculus -a tightly crosslinked peptidoglycan mesh unique to bacteria. Cell-wall synthesis and recycling are critical cellular processes essential for cell growth, elongation and division. Both de novo synthesis and recycling involve an array of enzymes across all cellular compartments, namely the outer membrane, periplasm, inner membrane and cytoplasm. Due to the exclusivity of peptidoglycan in the bacterial cell-wall, these players are the target of choice for many antibacterial agents. Our current understanding of cell-wall biochemistry and biogenesis in Gram-negative organisms stems mostly from studies of Escherichia coli. An incomplete knowledge on these processes exists for the opportunistic Gram-negative pathogen, Pseudomonas aeruginosa. In this review, cell-wall synthesis and recycling in the various cellular compartments are compared and contrasted between E. coli and P. aeruginosa. Despite the fact that there is a remarkable similarity of these processes between the two bacterial species, crucial differences alter their resistance to b-lactams, fluoroquinolones and aminoglycosides. One of the common mediators underlying resistance is the amp system whose mechanism of action is closely associated with the cell-wall recycling pathway. The activation of amp genes results in expression of AmpC blactamase through its cognate regulator AmpR which further regulates multi-drug resistance. In addition, other cell-wall recycling enzymes also contribute to antibiotic resistance. This comprehensive summary of the information should spawn new ideas on how to effectively target cell-wall processes to combat the growing resistance to existing antibiotics.

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“…A VAST search with D1 alone combined with bibliographical searches identified 4 structurally related families involved in polysaccharide recognition: the plant defense protein barwin (15), GH45 (3,(16)(17)(18), plant expansins (3), and family 2 of peptidoglycan lytic transglycosylases (LT), exemplified by MltA (19 (18)]. These proteins are quite divergent: pairwise sequence alignments with D1 range from 8% to 35% identity for most pairs (Table S2).…”

Section: Exlx1mentioning

confidence: 99%

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Kerff

Amoroso

Herman

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

183

291

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We solved the crystal structure of a secreted protein, EXLX1, encoded by the yoaJ gene of Bacillus subtilis. Its structure is remarkably similar to that of plant ␤-expansins (group 1 grass pollen allergens), consisting of 2 tightly packed domains (D1, D2) with a potential polysaccharide-binding surface spanning the 2 domains. Domain D1 has a double-␤-barrel fold with partial conservation of the catalytic site found in family 45 glycosyl hydrolases and in the MltA family of lytic transglycosylases. Domain D2 has an Ig-like fold similar to group 2/3 grass pollen allergens, with structural features similar to a type A carbohydratebinding domain. EXLX1 bound to plant cell walls, cellulose, and peptidoglycan, but it lacked lytic activity against a variety of plant cell wall polysaccharides and peptidoglycan. EXLX1 promoted plant cell wall extension similar to, but 10 times weaker than, plant ␤-expansins, which synergistically enhanced EXLX1 activity. Deletion of the gene encoding EXLX1 did not affect growth or peptidoglycan composition of B. subtilis in liquid medium, but slowed lysis upon osmotic shock and greatly reduced the ability of the bacterium to colonize maize roots. The presence of EXLX1 homologs in a small but diverse set of plant pathogens further supports a role in plant-bacterial interactions. Because plant expansins have proved difficult to express in active form in heterologous systems, the discovery of a bacterial homolog opens the door for detailed structural studies of expansin function.family 45 endoglucanase ͉ lytic transglycosylase ͉ peptidoglycan ͉ plant cell wall ͉ plant-microbe interactions B acterial and plant cell walls have similar functions but distinctive structures. Bacterial peptidoglycan forms a network of linear polysaccharide strands of alternating Nacetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues cross-linked by short polypeptides. As a giant bag-shaped sacculus, peptidoglycan expands via the action of endopeptidases, amidases, and lytic transglycosylases that cleave covalent bonds and allow insertion of new subunits (1). In contrast, the growing plant cell wall is formed from a scaffold of cellulose microfibrils tethered together by branched glycans such as xyloglucan or arabinoxylan that bind noncovalently to cellulose surfaces. The cellulose-hemicellulose network enlarges via polymer slippage or ''creep,'' mechanically powered by turgorgenerated forces in the cell wall and catalyzed by expansins and other wall-loosening agents (2).Expansins are known principally from plants where they function in cell enlargement and other developmental events requiring cell wall loosening (3). Canonical expansins are small proteins (Ϸ26 kDa, Ϸ225 aa) consisting of 2 compact domains: D1 has a fold similar to that of family 45 glycosyl hydrolases (GH45), and D2 has a ␤-sandwich fold. Expansins facilitate cell wall creep without breakdown of wall polymers (3-5). Plant expansins consist of 2 major families: ␣-expansins, which preferentially loosen the cell walls of dicots compa...

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Identification of Four Families of Peptidoglycan Lytic Transglycosylases

Cited by 127 publications

References 18 publications

The Essential Protein for Bacterial Flagella Formation FlgJ Functions as a β-N-Acetylglucosaminidase

The Essential Protein for Bacterial Flagella Formation FlgJ Functions as a β-N-Acetylglucosaminidase

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

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