scholarly journals Active-site and membrane topology of the DD-peptidase/penicillin-binding protein no. 6 of Enterococcus hirae (Streptococcus faecium) A.T.C.C. 9790

1989 ◽  
Vol 262 (2) ◽  
pp. 457-462 ◽  
Author(s):  
A el Kharroubi ◽  
G Piras ◽  
P Jacques ◽  
I Szabo ◽  
J Van Beeumen ◽  
...  

The membrane-bound 43,000-Mr penicillin-binding protein no. 6 (PBP6) of Enterococcus hirae consists of a 30,000-Mr DD-peptidase/penicillin-binding domain and a approximately 130-residue C-terminal appendage. Removal of this appendage by trypsin proteolysis has no marked effect on the catalytic activity and penicillin-binding capacity of the PBP. Anchorage of the PBP in the membrane appears to be mediated by a short 15-20-residue stretch at the C-terminal end of the appendage. The sequence of the 50-residue N-terminal region of the PBP shows high degree of homology with the sequences of the corresponding regions of the PBPs5 of Escherichia coli and Bacillus subtilis. On this basis the active-site serine residue occurs at position 35 in the enterococcal PBP.

1996 ◽  
Vol 40 (5) ◽  
pp. 1257-1259 ◽  
Author(s):  
A Yamane ◽  
H Nakano ◽  
Y Asahi ◽  
K Ubukata ◽  
M Konno

We investigated the molecular mechanism of 50 penicillin-resistant Streptococcus pneumoniae strains (penicillin: MIC, > or = 0.125 microgram/ml) having neither class A nor class B mutations in the penicillin-binding protein 2B gene (pbp2b). An analysis of the nucleotide sequences of the pbp2b genes from seven strains revealed an unique direct repeat of 9 nucleotides (TGGTATACT) between active-site serine (residue 385) and Ser-X-Asn (residues 442 to 444) motifs. The same insertion was detected in 13 strains.


1998 ◽  
Vol 42 (3) ◽  
pp. 534-539 ◽  
Author(s):  
Dominique Raze ◽  
Olivier Dardenne ◽  
Séverine Hallut ◽  
Manuel Martinez-Bueno ◽  
Jacques Coyette ◽  
...  

ABSTRACT Two plasmid-derived NcoI DNA fragments of 14 and 4.5 kb, respectively, have been isolated from the multidrug-resistant strain Enterococcus hirae S185R and analyzed. The 14-kb fragment contains two inverted (L and R) IS1216 insertion modules of the ISS1 family. These modules define a Tn5466 transposon-like structure that contains one copy of the methylase-encoding ermAMconferring erythromycin resistance and one copy of the adenylyl-transferase-encoding aadE conferring streptomycin resistance. Immediately on the left side of IS1216L there occurs a copy of pbp3r encoding the low-affinity penicillin-binding protein (PBP) PBP3r, itself preceded by apsr-like gene (psr3r) that controls the synthesis of PBP3r. ermAM, aadE, and the transposase gene (tnp) of IS1216R have the same polarities, and these are opposite those of psr3r,pbp3r, and the tnp gene of IS1216L. The 4.5-kb fragment is a copy of the 4.5-kb sequence at the 5′ end of the 14-kb fragment, although it is not a restriction product of the 14-kb fragment. It contains three genes with the same polarity:psr3r, pbp3r, and tnp in an IS1216 element. Because of the very high degree of identity (99%) with the chromosomal psrfm and pbp5fmgenes of Enterococcus faecium D63R, it is proposed that both the psr3r and pbp3r genes were transferred from an E. faecium strain and inserted in a plasmid ofE. hirae. E. hirae is the first known bacterial species in which a low-affinity PBP-encoding gene has been found to be plasmid borne.


1994 ◽  
Vol 303 (2) ◽  
pp. 357-362 ◽  
Author(s):  
M P G van der Linden ◽  
L de Haan ◽  
O Dideberg ◽  
W Keck

Alignment of the amino acid sequence of penicillin-binding protein 5 (PBP5) with the sequences of other members of the family of active-site-serine penicillin-interacting enzymes predicted the residues playing a role in the catalytic mechanism of PBP5. Apart from the active-site (Ser44), Lys47, Ser110-Gly-Asn, Asp175 and Lys213-Thr-Gly were identified as the residues making up the conserved boxes of this protein family. To determine the role of these residues, they were replaced using site-directed mutagenesis. The mutant proteins were assayed for their penicillin-binding capacity and DD-carboxypeptidase activity. The Ser44Cys and the Ser44Gly mutants showed a complete loss of both penicillin-binding capacity and DD-carboxypeptidase activity. The Lys47Arg mutant also lost its DD-carboxypeptidase activity but was able to bind and hydrolyse penicillin, albeit at a considerably reduced rate. Mutants in the Ser110-Gly-Asn fingerprint were affected in both acylation and deacylation upon reaction with penicillin and lost their DD-carboxypeptidase activity with the exception of Asn112Ser and Asn112Thr. The Asp175Asn mutant showed wild-type penicillin-binding but a complete loss of DD-carboxypeptidase activity. Mutants of Lys213 lost both penicillin-binding and DD-carboxypeptidase activity except for Lys213His, which still bound penicillin with a k+2/K' of 0.2% of the wild-type value. Mutation of His216 and Thr217 also had a strong effect on DD-carboxypeptidase activity. Thr217Ser and Thr217Ala showed augmented hydrolysis rates for the penicillin acyl-enzyme. This study reveals the residues in the conserved fingerprints to be very important for both DD-carboxypeptidase activity and penicillin-binding, and confirms them to play crucial roles in catalysis.


1992 ◽  
Vol 282 (3) ◽  
pp. 781-788 ◽  
Author(s):  
B Granier ◽  
C Duez ◽  
S Lepage ◽  
S Englebert ◽  
J Dusart ◽  
...  

As derived from gene cloning and sequencing, the 489-amino-acid DD-peptidase/penicillin-binding protein (PBP) produced by Actinomadura R39 has a primary structure very similar to that of the Escherichia coli PBP4 [Mottl, Terpstra & Keck (1991) FEMS Microbiol. Lett. 78, 213-220]. Hydrophobic-cluster analysis of the two proteins shows that, providing that a large 174-amino-acid stretch is excluded from the analysis, the bulk of the two polypeptide chains possesses homologues of the active-site motifs and secondary structures found in the class A beta-lactamase of Streptomyces albus G of known three-dimensional structure. The 174-amino-acid insert occurs at equivalent places in the two PBPs, between helices alpha 2 and alpha 3, away from the active site. Such an insert is unique among the penicilloyl serine transferases. It is proposed that the Actinomadura R39 PBP and E. coli PBP4 form a special class, class C, of low-Mr PBPs/DD-peptidases. A vector has been constructed and introduced by electrotransformation in the original Actinomadura R39 strain, allowing high-level expression and secretion of the DD-peptidase/PBP (250 mg.l-1). The gene encoding the desired protein is processed differently in Actinomadura R39 and Streptomyces lividans. Incorrect processing in Streptomyces lividans leads to a secreted protein which is inert in terms of DD-peptidase activity and penicillin-binding capacity.


1991 ◽  
Vol 280 (2) ◽  
pp. 463-469 ◽  
Author(s):  
A el Kharroubi ◽  
P Jacques ◽  
G Piras ◽  
J Van Beeumen ◽  
J Coyette ◽  
...  

The penicillin-resistant Enterococcus hirae R40 has a typical profile of membrane-bound penicillin-binding proteins (PBPs) except that the 71 kDa PBP5 of low penicillin affinity represents about 50% of all the PBPs present. Water-soluble tryptic-digest peptides were selectively produced from PBP5, their N-terminal regions were sequenced and synthetic oligonucleotides were used as primers to generate a 476 bp DNA fragment by polymerase chain reaction. On the basis of these data, the PBP5-encoding gene was cloned in Escherichia coli by using pBR322 as vector. The gene, included in a 7.1 kb insert, had the information for a 678-amino acid-residue protein. PBP5 shows similarity, in the primary structure, with the high-molecular-mass PBPs of class B. In particular, amino acid alignment of the enterococcal PBP5 and the methicillin-resistant staphylococcal PBP2′ generates scores that are 30, for the N-terminal domains, and 53, for the C-terminal domains, standard deviations above that expected for a run of 20 randomized pairs of proteins having the same amino acid compositions as the two proteins under consideration.


1992 ◽  
Vol 288 (1) ◽  
pp. 87-91 ◽  
Author(s):  
P Palomeque-Messia ◽  
V Quittre ◽  
M Leyh-Bouille ◽  
M Nguyen-Distèche ◽  
C J L Gershater ◽  
...  

Though synthesized with a cleavable signal peptide and devoid of membrane anchors, the 262-amino-acid-residue Streptomyces K15 DD-transpeptidase/penicillin-binding protein is membrane-bound. Overexpression in Streptomyces lividans resulted in the export of an appreciable amount of the synthesized protein (4 mg/litre of culture supernatant). The water-soluble enzyme was purified close to protein homogeneity with a yield of 75%. It requires the presence of 0.5 M-NaCl to remain soluble. It is indistinguishable from the detergent-extract wild-type enzyme with respect to molecular mass, thermostability, transpeptidase activity and penicillin-binding capacity.


1989 ◽  
Vol 260 (2) ◽  
pp. 601-604 ◽  
Author(s):  
M Leyh-Bouille ◽  
J Van Beeumen ◽  
S Renier-Pirlot ◽  
B Joris ◽  
M Nguyen-Distèche ◽  
...  

The N-terminal region of the Streptomyces K15 DD-peptidase/penicillin-binding protein shows high homology with that of other penicillin-interactive proteins or domains. The active-site serine residue of the conserved tetrad Ser-Xaa-Xaa-Lys occurs at position 35. There is no indication for the presence of a signal peptide or an N-terminal hydrophobic sequence, suggesting that the Streptomyces K15 enzyme is probably anchored to the membrane by a C-terminal peptide segment.


1985 ◽  
Vol 164 (1) ◽  
pp. 456-460 ◽  
Author(s):  
R A Nicholas ◽  
J L Strominger ◽  
H Suzuki ◽  
Y Hirota

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