Mur1, a Streptococcus thermophilus peptidoglycan hydrolase devoid of a specific cell wall binding domain

Husson-Kao, Clara

doi:10.1016/s0378-1097(00)00167-1

Cited by 11 publications

(16 citation statements)

References 17 publications

(30 reference statements)

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“…Eight of the 16 proteins with apparent signal sequences involved in active secretion have not been previously described for GAS (Table 3). These eight proteins include homologues of peptidoglycan hydrolase (SP23) (18), class B phosphatase (SPIX) (42,47), serine protease (SP24) (50), cyclodextrin glucosyltransferase (SP30) (4), a putative secreted protein made in abundance by L. lactis (SP35) (48), an immunogenic secreted protein made by GAS (SP13) (31), a protein with regions of homology with human Mac-1 (SP22) (2,7,53), and a protein with no known homologue (SP27).…”

Section: Discussionmentioning

confidence: 99%

“…The numbered and lettered triangles indicate the proteins reactive in the Western blots that correspond to the protein spots (numbered identically) in Fig. 1. SP23 has 46% amino acid sequence identity with Streptococcus thermophilus peptidoglycan hydrolase (18). Both of these streptococcal proteins lack the domain located in the carboxy terminus of the L. lactis major autolysin that is involved in cell wall binding.…”

Section: Discussionmentioning

confidence: 99%

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Identification and Immunogenicity of Group AStreptococcusCulture Supernatant Proteins

et al. 2000

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Extracellular proteins made by group A Streptococcus (GAS) play critical roles in the pathogenesis of human infections caused by this bacterium. Although many extracellular GAS proteins have been identified and characterized, there has been no systematic analysis of culture supernatant proteins. Proteins present in the culture supernatant of strains of serotype M1 (MGAS 5005) and M3 (MGAS 315) mutants lacking production of the major extracellular cysteine protease were separated by two-dimensional gel electrophoresis and identified by amino-terminal amino acid sequencing and interrogation of available databases, including a serotype M1 genome sequence. In the aggregate, amino-terminal amino acid sequence data for 66 protein spots were generated, 53 unique sequences were obtained, and 44 distinct proteins were identified. Sixteen of the 44 proteins had apparent secretion signal sequences and 27 proteins did not. Eight of the 16 proteins with apparent secretion signal sequences have not been previously described for GAS. Antibodies against most of the apparently secreted proteins were present in sera from mice infected subcutaneously with MGAS 5005 or MGAS 315. Humans with documented GAS infections (pharyngitis, acute rheumatic fever, and severe invasive disease) also had serum antibodies reacting with many of the apparently secreted proteins, indicating that they were synthesized in the course of GAS-human interaction. The genes encoding four of the eight previously undescribed and apparently secreted culture supernatant proteins were cloned, and the proteins were overexpressed in Escherichia coli. Western blot analysis with these recombinant proteins and sera from GASinfected mice and humans confirmed the immunogenicity of these proteins. Taken together, the data provide new information about the molecular aspects of GAS-host interactions.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Identification and Immunogenicity of Group AStreptococcusCulture Supernatant Proteins

et al. 2000

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“…The S. thermophilus cells used as substrates for lytic activity were prepared as previously described (39) with the following modification: after lyophilization, cells were resuspended in distilled water at a 10% final concentration and autoclaved for 20 min at 120°C. S. thermophilus proteins were extracted by glass bead disruption of cells as previously described (17). After electrophoresis, gels were gently shaken in 100 ml of water at 4°C for 1 h. Then water was replaced by 100 ml of 20 mM Tris-HCl (pH 7) containing 1% (vol/vol) Triton X-100 for overnight incubation at 42°C.…”

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confidence: 99%

cse , a Chimeric and Variable Gene, Encodes an Extracellular Protein Involved in Cellular Segregation in Streptococcus thermophilus

et al. 2005

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The isolation of a Streptococcus thermophilus CNRZ368 mutant displaying a long-chain phenotype allowed us to identify the cse gene (for cellular segregation). The N terminus of Cse exhibits high similarity to Streptococcus agalactiae surface immunogenic protein (SIP), while its C terminus exhibits high similarity to S. thermophilus PcsB. In CNRZ368, deletion of the entire cse open reading frame leads to drastic lengthening of cell chains and altered colony morphology. Complementation of the ⌬cse mutation with a wild-type allele restored both wild-type phenotypes. The central part of Cse is a repeat-rich region with low sequence complexity. Comparison of cse from CNRZ368 and LMG18311 strains reveals high variability of this repeat-rich region. To assess the impact of this central region variability, the central region of LMG18311 cse was exchanged with that of CNRZ368 cse. This replacement did not affect chain length, showing that divergence of the central part does not modify cell segregation activity of Cse. The structure of the cse locus suggests that the chimeric organization of cse results from insertion of a duplicated sequence deriving from the pcsB 3 end into an ancestral sip gene. Thus, the cse locus illustrates the module-shuffling mechanism of bacterial gene evolution.

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“…Very recently, a similar PGH, exhibiting 35% sequence identity with L. citreum Mur, was identified in the lactic acid bacterium Streptococcus thermophilus (26). Despite the lack of amino acid repeats, L. citreum Mur is endowed with peptidoglycan-hydrolyzing activity, as detected in vitro (Fig.…”

Section: Discussionmentioning

confidence: 85%

“…Southern hybridization was carried out with a 276-bp probe derived from the L. citreum mur sequence with the DNA of several Leuconostoc strains (16) (26), and a homologous one was identified in the complete sequence of L. lactis IL1403 (A. Bolotin and A. Sorokin, personal communication). All these data suggest a wide distribution of the gene, both in Leuconostoc spp.…”

Section: Resultsmentioning

confidence: 99%

Identification of Mur, an Atypical Peptidoglycan Hydrolase Derived fromLeuconostoc citreum

Cibik¹,

Tailliez²,

Langella³

et al. 2001

Appl Environ Microbiol

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A gene encoding a protein homologous to known bacterial N-acetyl-muramidases has been cloned from Leuconostoc citreum by a PCR-based approach. The encoded protein, Mur, consists of 209 amino acid residues with a calculated molecular mass of 23,821 Da including a 31-amino-acid putative signal peptide. In contrast to most of the other known peptidoglycan hydrolases, L. citreum Mur protein does not contain amino acid repeats involved in cell wall binding. The purified L. citreum Mur protein was shown to exhibit peptidoglycanhydrolyzing activity by renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An active chimeric protein was constructed by fusion of L. citreum Mur to the C-terminal repeat-containing domain (cA) of AcmA, the major autolysin of Lactococcus lactis. Expression of the Mur-cA fusion protein was able to complement an acmA mutation in L. lactis; normal cell separation after cell division was restored by Mur-cA expression.Bacteria produce one or several peptidoglycan hydrolases (PGHs), which are capable of hydrolyzing covalent bonds in the peptidoglycan of their own cell envelope (for reviews, see references 46 and 49). Some of them, named autolysins, are able to trigger cell autolysis. PGHs are located in the cell wall and are involved in various cellular functions, including cell wall expansion, cell wall turnover, or cell separation. On the basis of their cleavage site in the peptidoglycan, four types of PGHs are defined: (i) N-acetyl-muramidases, (ii) N-acetyl-glucosaminidases, (iii) N-acetyl-muramoyl-L-alanine amidases, and (iv) peptidases. Most of the PGHs characterized so far have a modular structural organization with two domains: a catalytic domain containing the enzyme active site and a cell wall binding domain composed of several amino acid repeats (22,30).Autolysis of lactic acid bacteria (LAB) used as starters for cheese manufacturing plays an important role in flavor development during ripening (for reviews, see references 13 and 18). It has been shown that lysis of Lactococcus lactis starter strains leads to the release of intracellular peptidases in the cheese curd, and as a result more free amino acids (which are aroma precursors) are produced and hydrophobic bitter peptides are degraded (12,35,52).The PGH activities present in L. lactis were studied by renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), which allowed their detection after renaturation in a substrate-containing gel. Several activity bands were evidenced by this technique (9, 36, 40, 44). The major autolysin, AcmA, was characterized at the genetic level. It is an N-acetyl-muramidase that is required for proper cell separation after cell division (9) and is involved in autolysis observed during stationary phase after growth in liquid medium (10).Leuconostocs are heterofermentative LAB used as cheese starters in association with lactococci. They contribute to the development of cheese organoleptic properties by metabolizing citrate to diacetyl, an important flavor compound, an...

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Mur1, a Streptococcus thermophilus peptidoglycan hydrolase devoid of a specific cell wall binding domain

Cited by 11 publications

References 17 publications

Identification and Immunogenicity of Group AStreptococcusCulture Supernatant Proteins

Identification and Immunogenicity of Group AStreptococcusCulture Supernatant Proteins

cse , a Chimeric and Variable Gene, Encodes an Extracellular Protein Involved in Cellular Segregation in Streptococcus thermophilus

Identification of Mur, an Atypical Peptidoglycan Hydrolase Derived fromLeuconostoc citreum

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