2026/04/17 by Thuc- Anh Dinh, Nanqi Jiang, Kimberly B. Lyons +5 · 1 voice
Biochemistry, Genetics and Molecular Biology · Nursing · #Bacterial Genetics and Biotechnology #Heat shock proteins research #Trace Elements in Health
paper · pdf · doi:10.1016/j.jbc.2026.111477
openalex publication_date 2026/04/17 · openalex created_date 2026/04/18 · openalex updated_date 2026/07/23
[NiFe] hydrogenases are widespread microbial metalloenzymes that catalyze the reversible conversion of hydrogen (H 2 ) to protons and electrons, playing key roles in energy metabolism. The biosynthesis of the NiFe(CN) 2 CO cofactor involves a suite of maturation proteins including the HypA and HypB nickel metallochaperones. Here, we define the metal-binding properties, nucleotide-dependent behavior, and functional interplay of HypA and HypB from the hydrogenotrophic methanogenic archaeon, Methanococcus maripaludis . Methanogens have multiple essential nickel-dependent enzymes, so they require efficient systems for nickel delivery that remain largely unexplored. Purified M. maripaludis HypA binds zinc or mononuclear iron at the C-terminal metal binding site, the latter of which has not been reported in other HypA proteins and may serve a unique regulatory role in methanogens. The G-protein metallochaperone HypB binds nickel at the G-domain, which stimulates GTPase activity. Size exclusion chromatography experiments reveal that HypA and HypB form complexes in the presence of nickel, and zinc-bound HypA is optimized for nickel transfer from HypB. The identity of the nucleotide bound to HypB (GDP or GTP) alters the oligomeric state of HypA-HypB complexes, supporting a GTPase-mediated nickel delivery pathway. The HypA-HypB 2 complex configuration is enriched and stable in the presence of GDP and nickel, indicating that this complex delivers nickel to the hydrogenase as opposed to HypA alone. Interestingly, affinity purification-mass spectrometry revealed that HypB interacts with several nickel-dependent proteins, suggesting that HypB may play a broader role in nickel homeostasis in M. maripaludis . Together, this work establishes a biochemical framework for HypAB-mediated nickel trafficking in methanogens.