Acta crystallographica. Section F, Structural biology communications最新文献

Piperine has been investigated for a diverse array of biological effects, including a potential role in modulating peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear receptor that plays a pivotal role in regulating lipid and glucose metabolism. This study conducted a comprehensive co-crystallographic analysis of the complex of piperine with the PPARγ ligand-binding domain (PPARγ-LBD), with the objective of elucidating the precise binding interactions of piperine. The co-crystal structure revealed that piperine binds within the ligand-binding pocket of PPARγ-LBD via hydrogen-bonding and hydrophobic interactions with residues of the ligand-binding site. Notably, in contrast to conventional full agonists, piperine does not directly stabilize helix H12. This could contribute to the comparatively weaker agonistic activity of piperine. The results of this study also suggest that piperine binding facilitates a role as a partial agonist or even an antagonist under certain physiological conditions. Collectively, these findings contribute to a greater understanding of the manner in which piperine modulates PPARγ function and its potential as a therapeutic candidate for the treatment of metabolic disorders. Given its natural origin and relatively minimal side-effect profile, piperine and its derivatives could be promising alternatives to synthetic PPARγ modulators such as thiazolidinediones, which have significant side effects.

The name of one of the authors in the article by Patil et al.[(2009), Acta Cryst. F65, 736–738] is corrected.

Immunoglobulin A (IgA) proteases are a group of bacterial-derived enzymes that selectivity hydrolyze human IgA in the hinge region that is unique to this immunoglobulin. Several IgA protease (IgAP) families have evolved this ability using both metalloprotease and serine protease chemical mechanisms. One family of metal-dependent IgAPs is the M26 family. This family can be grouped into two subfamilies based upon the presence or absence of a trypsin-like domain found N-terminal to the IgAP domain. The role of this domain in IgAP structure and function is poorly understood. Here, we present the first structural characterization of an M26 IgAP trypsin-like domain from Gemella haemolysans (GhTrp). These structural data demonstrate that the GhTrp domain possesses a trypsin-like fold but contains significant deviations in the surface-loop structure that is known to be coupled to protease selectivity. The lack of observable catalytic function coupled with the structural data suggest that this domain may exist in a pro-enzyme-like state that can potentially be activated when the domain is N-terminally proteolytically excised from the larger M26 IgAP structure.

Corrections are made to the article by Ando et al. [(2025), Acta Cryst. F81, 95-100].

Legionella pneumophila serogroup 1 is the primary causative agent of Legionnaires' disease, a rare but severe respiratory infection. While the fatality rate of Legionnaires' disease is low in the general population, it is more pronounced in vulnerable communities such as the immunocompromised. Thus, the development of new antimicrobials is of interest for use when existing antibiotics may not be applicable. Peptide deformylases (PDFs) have been under continued investigation as targets for novel antimicrobial compounds. PDF plays an essential role in protein synthesis, removing the N-terminal formyl group from new polypeptides, and is required for growth in most bacteria. Here, we report two crystal structures of L. pneumophila serogroup 1 PDF (LpPDF) bound to either Ni²⁺, an active state, or inhibited by actinonin and Zn²⁺; the structures were determined to 1.5 and 1.65 Å resolution, respectively, and were solved by the Seattle Structural Genomics Center for Infectious Disease (SSGCID). The SSGCID is charged with determining structures of biologically important proteins and molecules from human pathogens. As actinonin is an antimicrobial natural product that has been used as a reference compound in drug development, these structures will help support the ongoing drug-development process.

Photosynthesis is the largest-scale energy and material conversion process on Earth. The cytchrome (Cyt) b₆f complex plays a crucial role in photosynthesis. Under high-light conditions, cyclophilin 37 (CYP37) in Arabidopsis thaliana (AtCYP37) can interact with the PetA subunit of Cyt b₆f, thereby helping plants initiate photoprotection. Here, we purified, crystallized and determined a 1.95 Å resolution structure of AtCYP37. Overall, AtCYP37 consists of an N-terminal domain dominated by α-helices and a C-terminal domain mainly composed of β-strands and random coils. The structure shows significant similarity to those of Anabaena sp. CYPA and A. thaliana CYP38. Understanding the structure of AtCYP37 is significant as it may help to decipher how plants regulate photosynthesis and protect against high light damage, contributing to a broader understanding of plant photobiology and potentially guiding future research in improving plant stress tolerance.

Cellular deoxyuridine 5′-triphosphate nucleotidohydrolases (dUTPases) catalyze the hydrolysis of deoxyuridine triphosphate (dUTP) to deoxyuridine monophosphate (dUMP) and pyrophosphate (PP_i). dUTPase is an essential metabolic enzyme which maintains the homeostatic dTTP:dUTP ratio. As DNA polymerases are unable to distinguish between thymine and uracil during replication, the dTTP:dUTP ratio is essential for preventing the misincorporation of uracil into DNA. In the absence of dUTPase regulation of the dTTP:dUTP ratio, many DNA double-strand breaks are induced by DNA-repair enzymes, which may ultimately lead to cell death. Legionnaires' disease is a rare but severe respiratory infection caused primarily by Legionella pneumophila serogroup 1. Increased characterization of the L. pneumophila proteome is of interest for the development of new treatments. Many DNA metabolism proteins have yet to be characterized in L. pneumophila, including dUTPase. Here, we present analysis of two crystal structures of L. pneumophila dUTPase in its apo and dUMP-bound states, determined to 1.80 and 1.95 Å resolution, respectively. The structures were solved by the Seattle Structural Genomics Center for Infectious Disease (SSGCID) as part of their mission to determine structures of proteins and other molecules with an important biological role in human pathogens.