Crystallographic Structure Research Articles

Morphological Evolution of Metal‐Organic Frameworks into Hedrite, Sheaf and Spherulite Superstructures with Localized Different Coloration

The branched metal‐organic frameworks (MOFs) are the first superstructures of this kind, and the growth mechanism may explain crystal shapes of other materials. The mechanism of the formation of fascinating structures having a hedrite, sheaf or spherulite appearance are detailed. The branching can be controlled, resulting in crystals that either exhibit multiple generations of branching or a single generation. These structures might result from an increasing number of defects on fast‐grown rods. As the basal facets become less reactive, material is added to the prism facets, leading to secondary nucleation and triangular branches. These triangular structures are connected to the rod surface, growing longer than the central rod. Electron diffraction analyses show that the sheafs are polycrystalline structures with their fantails consisting of single‐crystalline nanorods deviating gradually from each‐other in their orientation. The crystallographic structure formed from achiral components consists of helical channels with opposite handedness. The accessibility of the nanochannels and the porosity of the superstructures are demonstrated by chromophore diffusion into the channels. The confinement and alignment of the chromophores inside the channels resulted in polarized‐light dependent coloration of the crystals; the polycrystallinity generated areas having different optical properties.

Why is binding of a divalent metal cation to a structural motif containing four carboxylate residues not accompanied by a conformational change?

We earlier showed that Torpedo californica acetylcholinesterase (AChE) contains a cluster of four conserved aspartates that can strongly bind divalent cations, which we named the 4D motif. Binding of the divalent metal cations greatly increases its thermal stability. Here we systematically examined all available crystallographic structures of T. californica AChE. Two additional metal-binding sites were identified, both composed of acidic and histidine residues. Relative binding to the 4D and additional sites was studied using metadynamics simulations. It was observed that in crystal structures devoid of metal ions in the 4D site, the conformation of T. californica AChE is almost identical to that in structures in which it is occupied by a divalent metal ion. Closer examination of the 4D motif reveals that three of the four acidic residues form ion pairs with conserved basic residues surrounding them. We named this new motif the 4A/3B motif. Molecular dynamics with quantum potential simulations was used to quantify the 4D motif's binding strength compared with that of the metal-binding site in the protein fXIIIa, which consists of four aspartates, but is devoid of adjacent cationic residues. Whereas fXIIIa's 4D site, in the absence of a metal cation, expanded significantly in the simulation, that of Torpedo AChE displayed only minor periodic changes in size. Furthermore, the energy of metal ion unbinding from the two sites differs by ca. 10 kcal/mol. We identified several other proteins in the PDB that contain the 4A/3B motif, whose conformations are identical in the presence or absence of a metal ion. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at https://proteopedia.org/w/Journal:Protein_Science:4.

Transport phase diagram and anomalous metallicity in superconducting infinite-layer nickelates.

Despite obvious similarities in their electronic and crystallographic structures, it remains unclear whether the interactions that shape the normal and superconducting (SC) state properties of high-Tc cuprates and infinite-layer nickelates (ILNs) have the same origin. This question has been brought into sharper focus with recent studies on ILNs of improved crystallinity that reveal a SC dome of comparable extent and similar transport properties above Tc as the hole-doped cuprates. The evolution of these properties in the magnetic-field-induced normal state, however, has yet to be determined. Here, we examine the magnetotransport properties of new-generation Nd1-xSrxNiO2 films in the T→0 limit across the phase diagram in fields up to 54 T. This extensive study reveals that the limiting low-T form of the normal-state resistivity in ILNs exhibits non-Fermi-liquid behaviour over an extended doping range inside the SC dome, rather than at a singular quantum critical point. While there are clear differences in the charge dynamics of ILNs and cuprates, most notably in the magnetoresistance, our findings reveal that both systems exhibit anomalous metallicity characteristic of a quantum critical phase.

Energy-resolved neutron imaging study of a Japanese sword signed by Bishu Osafune Norimitsu.

Our research focuses on elucidating the crystallographic structure of Japanese swords in a nondestructive manner using the neutron imaging instrument RADEN at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex(J-PARC). We developed an analysis method combining wavelength-resolved Bragg-edge imaging and wavelength-selective neutron tomography with a new strategy and applied it to an approximately 45-cm blade length Japanese sword signed by Bishu Osafune Norimitsu. Computed tomography was performed, and the three-dimensional analysis captured the characteristic internal structure of Kobuse. Kobuse is the most famous steel-combining structure of Japanese swords, where an outer steel with high-carbon content (Kawagane) covers a core steel with low-carbon content (Shingane). The crystallite size distribution obtained through Bragg-edge analysis could consistently explain the internal structure of two steels observed in neutron tomograms. Our nondestructive imaging revealed deep hardening, forming a wavy pattern more than 5mm from the cutting edge.

In Silico Efficacy of Oleic Acid, n-Hexanoic acid, and Epiglobulol Obtained from Conocarpus Lancifolius against Class D β-lactamases

Introduction: Antimicrobial resistance poses an escalating global challenge, compounded by the sluggish pace of new antibiotic discovery. Objectives: This study undertook an in silico analysis of phytochemicals derived from Conocarpus lancifolius, a local plant in the Jazan region of Saudi Arabia, to investigate potential antibacterial agents. Methods: The 3D crystallographic structure of OXA-48 was sourced from the RCSB protein databank (PDBID: 3HBR) and pre-processed. The Lib Dock algorithm facilitated the analysis of optimal binding orientations and potential interactions between compounds and the 3HBR. Results: The docking analysis outcome revealed Oleic acid as the most active compound and the binding mode exhibited that the -OH group of the terminal carboxylic acid moiety formed hydrogen bonds with Thr197 and Ala207, and the oxygen atom showed bonding with Lys116. Moreover, N-hexanoic acid also demonstrated promising binding interactions with the 3HBR, displaying hydrogen bond interactions with Lys208, Tyr211, and Ser70, along with hydrophobic alkyl interactions with Lys208 and Met115 at the protein's active sites. Unfavourable donor-donor and acceptor-acceptor bindings were also observed with Ser70 and Arg250 residues. Conclusions: The OXA-48 and NDM-1 predominate in countries of the Arabian Peninsula. Our findings suggest oleic acid as a promising candidate for combating OXA-48 β-lactamase, pending further assessment of its atomic structure via X-ray crystallography.

Inverse Design of Singlet‐Fission Materials with Uncertainty‐Controlled Genetic Optimization

AbstractSinglet fission has shown potential for boosting the efficiency of solar cells, but the scarcity of suitable molecular materials hinders its implementation. We introduce an uncertainty‐controlled genetic algorithm (ucGA) based on ensemble machine learning predictions from different molecular representations that concurrently optimizes excited state energies, synthesizability, and exciton size for the discovery of singlet fission materials. The ucGA allows us to efficiently explore the chemical space spanned by the reFORMED fragment database, which consists of 45,000 cores and 5,000 substituents derived from crystallographic structures assembled in the FORMED repository. Running the ucGA in an exploitative setup performs local optimization on variations of known singlet fission scaffolds, such as acenes. In an explorative mode, hitherto unknown candidates displaying excellent excited state properties for singlet fission are generated. We suggest a class of heteroatom‐rich mesoionic compounds as acceptors for charge‐transfer mediated singlet fission. When included in larger donor‐acceptor systems, these units exhibit localization of the triplet state, favorable diradicaloid character and suitable triplet energies for exciton injection into semiconductor solar cells.

Crystallographic insights into lipid-membrane protein interactions in microbial rhodopsins

The primary goal of our work is to provide structural insights into the influence of the hydrophobic lipid environment on the membrane proteins (MPs) structure and function. Our work will not cover the well-studied hydrophobic mismatch between the lipid bilayer and MPs. Instead, we will focus on the less-studied direct molecular interactions of lipids with the hydrophobic surfaces of MPs. To visualize the first layer of amphiphiles surrounding MPs and analyze their interaction with the proteins, we use the available highest-quality crystallographic structures of microbial rhodopsins. The results of the structure-based analysis allowed us to formulate the hypothetical concept of the role of the nearest layer of the lipids as an integral part of the MPs that are important for their structure and function. We then discuss how the lipid-MPs interaction is influenced by exogenous hydrophobic molecules, noble gases, which can compete with lipids for the surface of MPs and can be used in the systematic approach to verify the proposed concept experimentally. Finally, we raise the problems of currently available structural data that should be overcome to obtain a more profound picture of the lipid-MP interactions.

Benchmark Investigation of SARS-CoV-2 Mutants’ Immune Escape with 2B04 Murine Antibody: A Step Towards Unraveling a Larger Picture

Even though COVID-19 is no longer the primary focus of the global scientific community, its high mutation rate (nearly 30 substitutions per year) poses a threat of a potential comeback. Effective vaccines have been developed and administered to the population, ending the pandemic. Nonetheless, reinfection by newly emerging subvariants, particularly the latest JN.1 strain, remains common. The rapid mutation of this virus demands a fast response from the scientific community in case of an emergency. While the immune escape of earlier variants was extensively investigated, one still needs a comprehensive understanding of how specific mutations, especially in the newest subvariants, influence the antigenic escape of the pathogen. Here, we tested comprehensive in silico approaches to identify methods for fast and accurate prediction of antibody neutralization by various mutants. As a benchmark, we modeled the complexes of the murine antibody 2B04, which neutralizes infection by preventing the SARS-CoV-2 spike glycoprotein’s association with angiotensin-converting enzyme (ACE2). Complexes with the wild-type, B.1.1.7 Alpha, and B.1.427/429 Epsilon SARS-CoV-2 variants were used as positive controls, while complexes with the B.1.351 Beta, P.1 Gamma, B.1.617.2 Delta, B.1.617.1 Kappa, BA.1 Omicron, and the newest JN.1 Omicron variants were used as decoys. Three essentially different algorithms were employed: forced placement based on a template, followed by two steps of extended molecular dynamics simulations; protein–protein docking utilizing PIPER (an FFT-based method extended for use with pairwise interaction potentials); and the AlphaFold 3.0 model for complex structure prediction. Homology modeling was used to assess the 3D structure of the newly emerged JN.1 Omicron subvariant, whose crystallographic structure is not yet available in the Protein Database. After a careful comparison of these three approaches, we were able to identify the pros and cons of each method. Protein–protein docking yielded two false-positive results, while manual placement reinforced by molecular dynamics produced one false positive and one false negative. In contrast, AlphaFold resulted in only one doubtful result and a higher overall accuracy-to-time ratio. The reasons for inaccuracies and potential pitfalls of various approaches are carefully explained. In addition to a comparative analysis of methods, some mechanisms of immune escape are elucidated herein. This provides a critical foundation for improving the predictive accuracy of vaccine efficacy against new viral subvariants, introducing accurate methodologies, and pinpointing potential challenges.

Enhanced Grain Boundary Resistance Resulting in High Permittivity and Low Dielectric Loss in CaCu3Ti4O12/LaNiO3

(1-X) CaCu3Ti4O12 + (X) LaNiO3 composite ceramics were fabricated using pre-reacted calcium copper titanate CaCu3Ti4O12 (CCTO) and lanthanum nickelate LaNiO3 (LNO) and their crystallographic structure and morphology were studied to measure dielectric, impedance, and conductivity values. X-ray diffraction peaks show that CCTO/LNO composites are in a cubic structure. Scanning electron microscopy images show denser and more uniform grains with thin grain boundaries and a smaller average grain size. The permittivity of CCTO is stable in the range 102–106 Hz, but the composites show huge progress in permittivity by space charge polarization and relaxation in the range 103–104 Hz, demonstrating improved dielectric properties. The 0.98(CaCu3Ti4O12)+0.02(LaNiO3) sample showed a dielectric constant of 2.58 × 104 at 1 kHz, which is superior to pure CCTO (2.28 × 104 at 1 kHz). The electrical behaviour of the metallic filler on the composites was investigated using impedance spectroscopy analysis. The resistance of grain boundary increases with LNO. Activation energies were found to be 0.92, 0.95, and 0.90 eV for x = 0.1, 0.2, and 0.3, respectively, and these values are better than that of pristine CCTO (0.85 eV) sample. These results indicate that the prepared CCTO/LNO samples could be useul for high energy applications.

The Microstructure and Corrosion Characteristic of Al-10 wt.%RE (Re= Ce, Nd, La, Y) binary Aluminum Alloys in Natural Seawater

This study presented a thorough investigation into the microstructure, precipitated phases, and corrosion resistance of Al-10wt%Ce, Al-10wt%Nd, Al-10wt%La, and Al-10wt%Y binary alloys when exposed to natural seawater. The microstructural analysis, conducted using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM), revealed the presence of distinct precipitated phases. The distinct precipitated phases Al3Ce, Al3Nd, Al11La3, and Al3Y, respectively, have different morphologies and are expected to influence the corrosion resistance. The corrosion behavior of these alloys was evaluated through natural seawater immersion tests and electrochemical experiments, which demonstrated varying degrees of corrosion resistance. The average corrosion mass loss rates and average corrosion depths of the alloys in natural seawater were found to follow the order: Al-Y<Al-Ce < Al-La < Al-Nd. Theoretical explanations for the experimental outcomes were provided by analyzing the different types of precipitates, the electronic structures, and the crystallographic structures of the rare earth elements involved. This research contributes valuable theoretical and empirical data, supporting the application of rare earth aluminum alloys in structural materials for marine equipment.

Dynamics of AKAP/Calmodulin complex is largely driven by ionic occupancy state.

AKAP79/150 is a scaffold protein found in dendritic spines and other neuronal compartments. It localizes and regulates phosphorylation by protein kinase A and C and is, in turn regulated by , mediated by Calmodulin (CaM). Thus, the interaction of AKAP79/150 with CaM is of biological interest. A 2017 study used a peptide cross linking coupled to mass spectrometry (XLMS) to identify the CaM binding site on AKAP79/150 and subsequently solved an X-ray crystallography structure of CaM in complex with a short helical AKAP79/150 peptide. The XRD structure revealed an unusual mixed ionic occupancy state of CaM as bound to the AKAP79/150 peptide. In this molecular dynamics-based study, we have explored the motional modes of the CaM-AKAP helix complex under three ionic occupancy conditions. Our results indicate that the dynamics of this CaM backbone is largely dominated by the ionic occupancy state. We find that binding of the AKAP79/150 peptide to CaM is not preferentially stabilized in energetic terms in the Ca2+ state as compared to apo. However, the Mg2+ state is destabilized energetically as compared to the apo state. In addition, in the Ca2+ state, the AKAP79/150 peptide appears to be preferentially stabilized by additional hydrogen bonds. Our simulations suggest that further structural biology studies should be carried out, with a focus on driving the system equilibrium to full occupancy. NMR studies may be able to capture conformational states which are not seen in crystals.

Crystal structure of the alternative complex III from the phototrophic bacterium Chloroflexus aurantiacus.

Alternative complex III (ACIII) is a multi-subunit quinol:electron acceptor oxidoreductase that couples quinol oxidation with transmembrane proton translocation in bacterial respiratory and photosynthetic electron transport chains. Four ACIII cryoelectron microscopy (cryo-EM) structures are known. However, the effects of cryo-EM versus X-ray crystallography structure determination on ACIII structure are unclear. Here, we report a 3.25Å crystal structure of photosynthetic ACIII from Chloroflexus aurantiacus (CaACIIIp), revealing eight subunits (ActA-G and I) with four iron-sulfur clusters and six c-type hemes, a menaquinol-binding site, and two proton translocation passages. Structural comparisons with the previously reported cryo-EM structures reveal slight local conformational changes in the solvent-exposed regions of ActB, ActD, ActG, and the transmembrane (TM) helix of subunit I. The regions conferring structural flexibility possess low sequence conservation across species. However, the core functional modules containing the menaquinol-binding pocket, redox centers, and proton translocation passages remain unchanged, preserving the enzyme's activity.

Experimental Realization of Fluoroborophene.

Borophene, an anisotropic metallic Dirac material exhibits superlative physical and chemical properties. While the lack of bandgap restricts its electronic chip applications, insufficient charge carrier density and electrochemical/catalytically active sites, restricts its energy storage and catalysis applications. Fluorination of borophene can induce bandgap and yield local electron injection within its crystallographic lattice. Herein, a facile synthesis of fluoroborophene with tunable fluorine content through potassium fluoride-assisted solvothermal-sonochemical combinatorial approach is reported. Fluoroborophene monolayers with lateral dimension 50 nm-5 µm are synthesized having controlled fluorine content (12-35%). Fluoroborophene exhibits inter-twinned crystallographic structure, with fluorination-tunable visible-range bandgap ≈1.5-2.5 eV, and density functional theory calculations also corroborate it. Fluoroborophene is explored for electrocatalytic oxygen evolution reaction in an alkaline medium and bestow a good stability. Tunable bandgap, electrophilicity and molecular anchoring capability of fluoroborophene will open opportunities for novel electronic/optoelectronic/spintronic chips, energy storage devices, and in numerous catalytic applications.

Novel Crystalline Salts of 4-Piperidyl- and 4-Pyridylmethylamines Prepared by Catalytic Hydrogenation of 4-Pyridinecarbonitrile: Crystallographic Unit Cells Based on Powder XRD Patterns by Using the DASH Program Package

Structures of some hydrogenated products and intermediates, prepared by a heterogeneous Pd/C or Ru/C catalyst starting from 4-pyridinecarbonitrile (4PN), in water and in the presence of an acidic additive (HCl or H2SO4), were confirmed in various salt forms of 4-piperidylmethylamine (4PIPA) and 4-pyridylmethylamine (4PA). Crystallographic unit cell structure of the completely hydrogenated product salts (4PIPA·H2SO4 and 4PIPA·2HCl) showed a common double-protonated [4PIPA+2H]2+ divalent cation structure, also proved by FT-IR, and that of the 4PA·H2SO4 intermediate salt was also indexed and modeled by means of powder X-ray diffraction, applying the DASH 4.0 software package and crystal coordinates coming from former single-crystal X-ray structure determination. Formations of the anhydrous and hydrated forms of 4PA·0.5H2SO4·xH2O (x = 0 or x = 0.5, hemisulfates) were also studied by powder XRD and FT-IR spectroscopy for comparing these crystal structures.

Enhanced cellular death in liver and breast cancer cells by dual BET/BRPF1 inhibitors.

The acetylpyrrole scaffold is an acetylated lysine mimic that has been previously explored to develop bromodomain inhibitors. When tested on the hepatoma cell line Huh7 and the breast cancer cell line MDA-MB-231, a few compounds in our acetylpyrrole-thiazole library induced peculiar morphological changes, progressively causing cell death at increasing concentrations. Their evaluation on a panel of human bromodomains revealed concurrent inhibition of BRPF1 and BET bromodomains. To dissect the observed cellular effects, the acetylpyrrole derivatives were compared to JQ1 and GSK6853, chemical probes for the bromodomains of BET and BRPF1, respectively. The appearance of neurite-like extrusions, accompanied by βIII-tubulin overexpression, is caused by BET inhibition, with limited effect on cellular viability. Conversely, interference with BRPF1 induces cellular death but not phenotypic alterations. Combined treatment with JQ1 and GSK6853 showed additivity in reducing cellular viability, comparably to the acetylpyrrole-thiazole-based BET/BRPF1 inhibitors. In addition, we determined the crystallographic structures of the BRD4 and BRPF1 bromodomains in complex with the acetylpyrrole-thiazole compounds. The binding modes in the two bromodomains show similar interactions for the acetylpyrrole and different orientations of the moiety that point to the rim of the acetyl-lysine pocket.

Crystal structure of a bacterial photoactivated adenylate cyclase determined by serial femtosecond and serial synchrotron crystallography.

OaPAC is a recently discovered blue-light-using flavin adenosine dinucleotide (BLUF) photoactivated adenylate cyclase from the cyanobacterium Oscillatoria acuminata that uses adenosine triphosphate and translates the light signal into the production of cyclic adenosine monophosphate. Here, we report crystal structures of the enzyme in the absence of its natural substrate determined from room-temperature serial crystallography data collected at both an X-ray free-electron laser and a synchrotron, and we compare these structures with cryo-macromolecular crystallography structures obtained at a synchrotron by us and others. These results reveal slight differences in the structure of the enzyme due to data collection at different temperatures and X-ray sources. We further investigate the effect of the Y6W mutation in the BLUF domain, a mutation which results in a rearrangement of the hydrogen-bond network around the flavin and a notable rotation of the side chain of the critical Gln48 residue. These studies pave the way for picosecond-millisecond time-resolved serial crystallography experiments at X-ray free-electron lasers and synchrotrons in order to determine the early structural intermediates and correlate them with the well studied picosecond-millisecond spectroscopic intermediates.

Cryo-EM structure of the human native plasma coagulation factor XIII complex

AbstractThe structure of human coagulation factor XIII (FXIII), a heterotetrameric plasma protransglutaminase that covalently cross-links preformed fibrin polymers, remains elusive until today. The heterotetrameric complex is composed of 2 catalytic FXIII-A and 2 protective FXIII-B subunits. Structural etiology underlying FXIII deficiency has so far been derived from crystallographic structures, all of which are currently available for the FXIII-A2 homodimer only. Here, we present the cryogenic electron microscopy structure of a native, human plasma–derived FXIII-A2B2 complex at 2.4 Å resolution. The structure provides detailed information on FXIII subunit interacting interfaces as the 2 subunits interact strongly in plasma. The native FXIII-A2B2 complex reveals a pseudosymmetric heterotetramer of 2 FXIII-B monomers intercalating with a symmetric FXIII-A2 dimer forming a “crown”-like assembly. The symmetry axes of the A2 and B2 homodimers are twisted relative to each other such that Sushi domain 1 interacts with the catalytic core of the A subunit, and Sushi domain 2 with the symmetry related A′ subunit, and vice versa. We also report 4 novel mutations in the F13A1 gene encoding the FXIII-A subunit from a cohort of patients with severe FXIII deficiency. Our structure reveals the etiological basis of homozygous and heterozygous pathogenic mutations and explains the conditional dominant negative effects of heterozygous mutations. This atomistic description of complex interfaces is consistent with previous biochemical data and shows a congruence between the structural biochemistry of the FXIII complex and the clinical features of FXIII deficiency.

Photocatalytic degradation of methylene blue using a Cu2+-modified bimetallic titanium-based metal organic framework (MIL-125) photocatalyst with enhanced visible light activity.

Cu-modified TiO2 nanoparticles derived from MIL-125 were prepared by solvothermal method for the photocatalytic degradation of methylene blue under visible light illumination. For boosting the photocatalytic performance as well as the physicochemical properties of bare sample, 2 wt % Cu2+ ions were integrated into the nodes of the MIL-125 framework. The results showed that incorporation of 2 wt % Cu2+ ions into the MOF framework had significant effects on the crystallographic structure and morphological and optical properties of photocatalytic samples, as well as catalytic activity for the methylene blue degradation reaction. The high activity profile of Cu-modified TiO2 nanoparticles derived from MIL-125 might be attributed to the increased thermal stability, lower band gap energy, and smaller crystallite size of the sample. Activity tests were carried out at five varying MB initial concentrations and four different pH values. According to the findings, an increase in initial dye concentration resulted in a decrease in degradation efficiency. It was observed that increasing the pH value in the range of 3-11 initially led to higher degradation rates until pH 7, after which the degradation rate began to decline.

RNase W, a conserved ribonuclease family with a novel active site.

Ribosome biogenesis is a complex process requiring multiple precursor ribosomal RNA (rRNA) cleavage steps. In archaea, the full set of ribonucleases (RNases) involved in rRNA processing remains to be discovered. A previous study suggested that FAU-1, a conserved protein containing anRNase G/E-like protein domain fused to a domain of unknown function (DUF402), acts as an RNase in archaea. However, the molecular basis of this activity remained so far elusive. Here, we report two X-ray crystallographic structures of RNase G/E-like-DUF402 hybrid proteins from Pyrococcus furiosus and Sulfolobus acidocaldarius, at 2.1 and 2.0 Å, respectively. The structures highlight a structural homology with the 5' RNA recognition domain of Escherichia coli RNase E but no homology with other known catalytic nuclease domains. Surprisingly, we demonstrate that the C-terminal domain of this hybrid protein, annotated as a putative diphosphatase domain, harbors the RNase activity. Our functional analysis also supports a model by which the RNase G/E-like domain acts as a regulatory subunit of the RNase activity. Finally, in vivo experiments in Haloferax volcanii suggest that this RNase participates in the maturation of pre-16S rRNA. Together, our study defines a new RNase family, which we termed the RNase W family, as the first archaea-specific contributor to archaeal ribosome biogenesis.

Azolium-Porphyrin Electrosynthesis.

Electrochemical oxidation of Zn(II) 2,7,12,17-tetra-tert-butylporphyrin in the presence of a series of azole derivatives (1-methylimidazole, 1-vinyl-1H-imidazole, 2-(1H-imidazol-1-yl)pyridine, 1-methylbenzimidazole, 1-methyl-1H-1,2,4-triazole, and benzothiazole) affords the corresponding meso-substituted azolium-porphyrins in very mild conditions and good yields. It was found that these nucleophiles were strongly ligated to the zinc(II) azolium-porphyrin complexes. Thus a demetalation/remetalation procedure was performed to recover the non-azole-coordinated zinc(II) complexes. X-ray crystallographic structures of three azolium-porphyrins were solved. Cyclic voltammetry analyses provided insight into the electron-withdrawing effect of the azolium substituents.