scholarly journals The Role of the β5–α11 Loop in the Active-Site Dynamics of Acylated Penicillin-Binding Protein A from Mycobacterium tuberculosis

2012 ◽  
Vol 418 (5) ◽  
pp. 316-330 ◽  
Author(s):  
Alena Fedarovich ◽  
Robert A. Nicholas ◽  
Christopher Davies
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Active Site ◽  
Binding Protein ◽  
Protein A ◽  
Penicillin Binding Protein

scholarly journals Crystal structures of the transpeptidase domain of the Mycobacterium tuberculosis penicillin-binding protein PonA1 reveal potential mechanisms of antibiotic resistance

FEBS Journal ◽  
2016 ◽  
Vol 283 (12) ◽  
pp. 2206-2218 ◽  
Author(s):  
Ekaterina V. Filippova ◽  
Karen J. Kieser ◽  
Chi-Hao Luan ◽  
Zdzislaw Wawrzak ◽  
Olga Kiryukhina ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Mycobacterium Tuberculosis ◽  
Crystal Structures ◽  
Binding Protein ◽  
Penicillin Binding Protein

scholarly journals Assessment of the Dual Role of Clumping Factor A in S. Aureus Adhesion to Endothelium in Absence and Presence of Plasma

2018 ◽  
Vol 118 (07) ◽  
pp. 1230-1241 ◽  
Author(s):  
Jorien Claes ◽  
Bartosz Ditkowski ◽  
Laurens Liesenborghs ◽  
Tiago Veloso ◽  
Jose Entenza ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Binding Protein ◽  
Protein A ◽  
Bacterial Proteins ◽  
Fibronectin Binding Protein ◽  
A Disintegrin And Metalloproteinase ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractAdhesion of Staphylococcus aureus to endothelial cells (ECs) is paramount in infective endocarditis. Bacterial proteins such as clumping factor A (ClfA) and fibronectin binding protein A (FnbpA) mediate adhesion to EC surface molecules and (sub)endothelial matrix proteins including fibrinogen (Fg), fibrin, fibronectin (Fn) and von Willebrand factor (vWF). We studied the influence of shear flow and plasma on the binding of ClfA and FnbpA (including its sub-domains A, A16+, ABC, CD) to coverslip-coated vWF, Fg/fibrin, Fn or confluent ECs, making use of Lactococcus lactis, expressing these adhesins heterologously. Global adherence profiles were similar in static and flow conditions. In the absence of plasma, L. lactis-clfA binding to Fg increased with shear forces, whereas binding to fibrin did not. The degree of adhesion of L. lactis-fnbpA to EC-bound Fn and of L. lactis-clfA to EC-bound Fg, furthermore, was similar to that of L. lactis-clfA to coated vWF domain A1, in the presence of vWF-binding protein (vWbp). Yet, in plasma, L. lactis-clfA adherence to activated EC-vWF/vWbp dropped over 10 minutes by 80% due to vWF-hydrolysis by a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 and that of L. lactis-fnbpA likewise by > 70% compared to the adhesion in absence of plasma. In contrast, plasma Fg supported high L. lactis-clfA binding to resting and activated ECs. Or, in plasma S. aureus adhesion to active endothelium occurs mainly via two complementary pathways: a rapid but short-lived vWF/vWbp pathway and a stable integrin-coupled Fg-pathway. Hence, the pharmacological inhibition of ClfA-Fg interactions may constitute a valuable additive treatment in infective endocarditis.

scholarly journals Directly repeated insertion of 9-nucleotide sequence detected in penicillin-binding protein 2B gene of penicillin-resistant Streptococcus pneumoniae.

1996 ◽  
Vol 40 (5) ◽  
pp. 1257-1259 ◽  
Author(s):  
A Yamane ◽  
H Nakano ◽  
Y Asahi ◽  
K Ubukata ◽  
M Konno
Keyword(s):  
Streptococcus Pneumoniae ◽  
Nucleotide Sequence ◽  
Molecular Mechanism ◽  
Active Site ◽  
Binding Protein ◽  
Direct Repeat ◽  
Penicillin Binding Protein ◽  
Serine Residue ◽  
Class A ◽  
Class B

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.

scholarly journals A Low-Affinity Penicillin-Binding Protein 2x Variant Is Required for Heteroresistance in Streptococcus pneumoniae

2014 ◽  
Vol 58 (7) ◽  
pp. 3934-3941 ◽  
Author(s):  
Hansjürg Engel ◽  
Moana Mika ◽  
Dalia Denapaite ◽  
Regine Hakenbeck ◽  
Kathrin Mühlemann ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Abc Transporter ◽  
Binding Protein ◽  
Population Analysis ◽  
Resistance Testing ◽  
Penicillin Binding Protein ◽  
Secondary Resistance ◽  
Content Type ◽  
Abc Transporter Genes

ABSTRACTHeteroresistance to penicillin inStreptococcus pneumoniaeis the ability of subpopulations to grow at a higher antibiotic concentration than expected from the MIC. This may render conventional resistance testing unreliable and lead to therapeutic failure. We investigated the role of the primary β-lactam resistance determinants, penicillin-binding protein 2b (PBP2b) and PBP2x, and the secondary resistance determinant PBP1a in heteroresistance to penicillin. Transformants containing PBP genes from the heteroresistant strain Spain23F2349in the nonheteroresistant strain R6 background were tested for heteroresistance by population analysis profiling (PAP). We found thatpbp2x, but notpbp2borpbp1aalone, conferred heteroresistance to R6. However, a change ofpbp2xexpression was not observed, and therefore, expression does not correlate with an increased proportion of resistant subpopulations. In addition, the influence of the CiaRH system, mediating PBP-independent β-lactam resistance, was assessed by PAP onciaRdisruption mutants but revealed no heteroresistant phenotype. We also showed that the highly resistant subpopulations (HOM*) of transformants containing low-affinitypbp2xundergo an increase in resistance upon selection on penicillin plates that partially reverts after passaging on selection-free medium. Shotgun proteomic analysis showed an upregulation of phosphate ABC transporter subunit proteins encoded bypstS,phoU,pstB, andpstCin these highly resistant subpopulations. In conclusion, the presence of low-affinitypbp2xenables certain pneumococcal colonies to survive in the presence of β-lactams. Upregulation of phosphate ABC transporter genes may represent a reversible adaptation to antibiotic stress.

scholarly journals Site-directed mutagenesis of proposed active-site residues of penicillin-binding protein 5 from Escherichia coli

1994 ◽  
Vol 303 (2) ◽  
pp. 357-362 ◽  
Author(s):  
M P G van der Linden ◽  
L de Haan ◽  
O Dideberg ◽  
W Keck
Keyword(s):  
Active Site ◽  
Catalytic Mechanism ◽  
Binding Capacity ◽  
Binding Protein ◽  
Complete Loss ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Penicillin Binding Protein ◽  
Wild Type ◽  
Active Site Residues

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.

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