Botulinum neurotoxins have been declared as a Category A agent by the Centers of Disease Control and Prevention owing to their extremely poisonous nature and are potential bioweapon and bioterrorism agents. Towards the discovery of antidotes, structures of inhibitory peptide-enzyme complexes were determined, the structure-activity relationship was determined and a pharmacophore was developed.

The co-crystal structure of the metallopeptidase astacin with its specific protein inhibitor fetuin-B reveals a novel mechanism of inhibition.

A combined co-crystallization/crystal-soaking procedure has been devised for the efficient structural elucidation of protein–peptide complexes.

This work reports the purification, biochemical characterization and high-resolution structures of two novel mevalonate kinases: one from the extremotolerant tardigrade Ramazzottius varieornatus at 2 Å resolution and one from the psychrophilic archaeon Methanococcoides burtonii at 2.2 Å resolution.

Crystal structures of peptide deformylase from S. aureus in complex with novel inhibitors are presented together with their functional analysis. A detailed comparative analysis of these structures as well as the activities of the inhibitors allowed the elucidation of distinctive structural changes which depend upon the class of inhibitor.

O-Acetylserine sulfhydrylase (OASS) from L. donovani can bind to serine acetyltransferase (SAT) C-terminus mimicking peptides with a range of bulkiness; the strength of these interactions correlates with the size of the peptide side chains and the size of the active-site cleft. Differences in the interactions of OASS and SAT from various species may be explained by the size of the active-site cleft.

The interaction between the integral membrane protein zinc metalloprotease ZMPSTE24 and the natural product broad-specificity zinc metalloprotease peptidic inhibitor phosphoramidon has been characterized functionally and structurally. The functional results demonstrate the sensitivity of ZMPSTE24 to phosphoramidon in a manner consistent with competitive inhibition, as in soluble zinc metalloproteases, and that the overall mode of binding of phosphoramidon to ZMPSTE24 and soluble zinc metalloproteases, especially gluzincins, is conserved.

P. falciparum orotate phosphoribosyltransferase, a potential target for antimalarial drugs and a conduit for prodrugs, crystallized as a structure with eight molecules per asymmetric unit that included some unique parasite-specific auto-inhibitory interactions between catalytic dimers.

The structure of the complex formed between Russell's viper phospholipase A₂ and a designed peptide LAIYS has been determined at 2.0 Å resolution. The peptide binds to phospholipase A₂ specifically and fills the hydrophobic channel completely.

The crystal structure of bacteriophage T4 Spackle as determined by sulfur SAD phasing reveals a monomeric protein with a helical bundle fold and a disc-like overall shape. Spackle has an intramolecular disulfide bond and a bipolar surface-charge distribution, which are consistent with its proposed role as a lysozyme inhibitor that functions in the Escherichia coli periplasm.