Related Experiment Video
Updated: Jun 26, 2026
11:42
Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Crystal structure of Streptococcus pyogenes sortase A: implications for sortase mechanism
Paul R Race1, Matthew L Bentley, Jeff A Melvin
1Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom.
The Journal of Biological Chemistry
|January 9, 2009
Summary
Sortases anchor proteins to bacterial surfaces, aiding virulence. Understanding the Streptococcus pyogenes sortase structure and catalysis offers new antimicrobial drug design strategies.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Sortases are Gram-positive bacterial transpeptidases essential for anchoring surface proteins.
- These enzymes are crucial for virulence and represent attractive antimicrobial targets.
- Housekeeping sortases recognize LPXTG motifs for cell wall anchoring.
Purpose of the Study:
- To elucidate the catalytic mechanisms and substrate recognition of the Streptococcus pyogenes housekeeping sortase.
- To determine the crystal structure of this sortase and establish its in vitro transpeptidase activity.
Main Methods:
- X-ray crystallography was used to solve the sortase structure.
- In vitro transpeptidase activity assays were performed.
- Chemical modifications of the active site cysteine were analyzed.
Main Results:
- A novel active site residue arrangement consistent with kinetic data was revealed.
- The structure provides a comprehensive view of the active site, resolving previous disorder.
- Evidence supports a reactive thiol/thiolate in the catalytic mechanism.
Conclusions:
- The determined structure offers new insights into sortase function.
- Understanding sortase mechanisms can guide the development of novel antimicrobial agents.
Related Concept Videos
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:20Determinants of Bacterial Pathogenicity and Virulence
Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
02:02DNA Topoisomerases
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
00:49Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...
01:27Streptococcal Pharyngitis
Streptococcal pharyngitis, commonly known as “strep throat,” is an acute infection of the oropharyngeal tissues caused by the Gram‑positive Group A Streptococcus (Streptococcus pyogenes). Transmission occurs primarily through respiratory droplets expelled during coughing, sneezing, or talking.Mechanisms of Host Entry and Immune EvasionUpon entering the host, S. pyogenes adheres to the mucosal epithelial cells of the pharynx via surface proteins, notably lipoteichoic acid and the antiphagocytic...
01:03Single-Strand DNA Binding Proteins
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...