Erratum: Monoclonal Anti-AMP Antibodies Are Sensitive and Valuable Tools for Detecting Patterns of AMPylation.

[This corrects the article DOI: 10.1016/j.isci.

Specificity of AMPylation of the human chaperone BiP is mediated by TPR motifs of FICD.

To adapt to fluctuating protein folding loads in the endoplasmic reticulum (ER), the Hsp70 chaperone BiP is reversibly modified with adenosine monophosphate (AMP) by the ER-resident Fic-enzyme FICD/HYPE. The structural basis for BiP binding and AMPylation by FICD has remained elusive due to the transient nature of the enzyme-substrate-complex. Here, we use thiol-reactive derivatives of the cosubstrate adenosine triphosphate (ATP) to covalently stabilize the transient FICD:BiP complex and determine its crystal structure.

Current Advances in Covalent Stabilization of Macromolecular Complexes for Structural Biology.

Structural characterization of macromolecular assemblies is often limited by the transient nature of the interactions. The development of specific chemical tools to covalently tether interacting proteins to each other has played a major role in various fundamental discoveries in recent years. To this end, protein engineering techniques such as mutagenesis, incorporation of unnatural amino acids, and methods using synthetic substrate/cosubstrate derivatives were employed.

Monoclonal Anti-AMP Antibodies Are Sensitive and Valuable Tools for Detecting Patterns of AMPylation.

AMPylation is a post-translational modification that modifies amino acid side chains with adenosine monophosphate (AMP). Recently, a role of AMPylation as a universal regulatory mechanism in infection and cellular homeostasis has emerged, driving the demand for universal tools to study this modification. Here, we describe three monoclonal anti-AMP antibodies (mAbs) from mouse that are capable of protein backbone-independent recognition of AMPylation, in denatured (western blot) as well as native (ELISA, IP) applications, thereby outperforming previously reported tools.

Identification of targets of AMPylating Fic enzymes by co-substrate-mediated covalent capture.

Various pathogenic bacteria use post-translational modifications to manipulate the central components of host cell functions. Many of the enzymes released by these bacteria belong to the large Fic family, which modify targets with nucleotide monophosphates. The lack of a generic method for identifying the cellular targets of Fic family enzymes hinders investigation of their role and the effect of the post-translational modification.

Sortase-Mediated Quantifiable Enzyme Immobilization on Magnetic Nanoparticles.

Protein immobilization has gained high interest in recent years for its valuable applications in life sciences involving drug delivery and protein arrays. Herein, we combine sortase-mediated protein immobilization with the versatility of magnetic nanoparticles and a sensitive GFP-based quantification system. Using this method, we successfully immobilized and quantified the amount of coupled enzymes by fluorescence spectroscopy and assessed their activity by kinetic measurements.