Maximillian K Osterberg, Ally Smith, Courtney Campbell, Daniel Deredge, Timothy L Stemmler, David P Giedroc
COG0523 proteins, also known as nucleotide-dependent metallochaperones, are a poorly understood class of small P-loop G3E GTPases. Multiple family members play critical roles in bacterial pathogen survival during an infection as part of the adaptive response to host-mediated "nutritional immunity." Our understanding of the structure, dynamics, and molecular-level function of COG0523 proteins, apart from the eukaryotic homologue, Zng1, remains in its infancy. Here, we use X-ray absorption spectroscopy to establish that Acinetobacter baumannii (Ab) ZigA coordinates ZnII using all three cysteines derived from the invariant CXCC motif to form an S3 (N/O) coordination complex, a feature inconsistent with an available ZnII -bound crystal structure of a distantly related COG0523 protein of unknown function from E...
March 8, 2024: Biophysical Journal