scholarly journals Two crystal forms of peptidylarginine deiminase typeIII (PAD3)

2014 ◽  
Vol 70 (a1) ◽  
pp. C937-C937
Author(s):  
Megumi Akimoto ◽  
Makiko Ishihara ◽  
Kenji Kizawa ◽  
Hidenari Takahara ◽  
Masaki Unno

Peptidylarginine deiminase (PAD) is a Ca2+-dependent enzyme that catalyzes the conversion of protein arginine residues to citrulline. Protein citrullination by PAD confers large structural and mechanical effects on the target proteins by altering intermolecular and intramolecular ionic or hydrophobic interactions. Five paralogous genes (PADI1 - 4 and 6) on human chromosome 1p35-36 encode the human PAD isozymes. Among the PADs, PAD3 shows the highest substrate specificity for synthetic and natural substrate. S100A3 is an EF-hand-type Ca2+-binding S100 protein family member that colocalizes with PAD3 in hair cuticular cells. PAD3 converts a symmetric pair of Arg51 residues on an S100A3 dimer surface to citrullines, causing assembly of a homotetramer, but does not convert other arginines. Although this specific citrullination is largely affected by the formation of two intramolecular disulfides in S100A3, it is not clear how the sheltered Arg51 residues is recognized by PAD3. We are aiming structural analysis of the substrate bound forms to elucidate structural factor that PAD3 recognize Arg51 residues only. Although X-ray crystal structures of the PAD4 isozyme and its complexes with substrate peptides have been reported, structural analysis of other PAD isozymes has not yet been conducted. To obtain the crystals of the substrate-complex, we prepared the C646A mutant and the other inactive mutants (D350A, H470A, D472A) of PAD3. We determined the crystal structures of wild-type PAD3, at first. Then, we have tried to determine the structure of the substrate complex with the mutants of PAD3. However, the solved structures did not contain the substrate at present stage. From our structural analysis, only the crystals of C646A were belonged to different crystal system from the others, and its difference didn't relate to their crystallization condition. In this conference, we discuss the origin(s) of the differences in the crystal system of C646 from the others.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fengbin Wang ◽  
Ordy Gnewou ◽  
Charles Modlin ◽  
Leticia C. Beltran ◽  
Chunfu Xu ◽  
...  

AbstractThe exquisite structure-function correlations observed in filamentous protein assemblies provide a paradigm for the design of synthetic peptide-based nanomaterials. However, the plasticity of quaternary structure in sequence-space and the lability of helical symmetry present significant challenges to the de novo design and structural analysis of such filaments. Here, we describe a rational approach to design self-assembling peptide nanotubes based on controlling lateral interactions between protofilaments having an unusual cross-α supramolecular architecture. Near-atomic resolution cryo-EM structural analysis of seven designed nanotubes provides insight into the designability of interfaces within these synthetic peptide assemblies and identifies a non-native structural interaction based on a pair of arginine residues. This arginine clasp motif can robustly mediate cohesive interactions between protofilaments within the cross-α nanotubes. The structure of the resultant assemblies can be controlled through the sequence and length of the peptide subunits, which generates synthetic peptide filaments of similar dimensions to flagella and pili.


Author(s):  
Shukun Luo ◽  
Ke Xu ◽  
Shaoyun Xiang ◽  
Jie Chen ◽  
Chunyun Chen ◽  
...  

Human indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-dependent enzyme with important roles in many cellular processes and is a potential target for drug discovery against cancer and other diseases. Crystal structures of IDO1 in complex with various inhibitors have been reported. Many of these crystals belong to the same crystal form and most of the reported structures have resolutions in the range 3.2–2.3 Å. Here, three new crystal forms of human IDO1 obtained by introducing a surface mutation, K116A/K117A, distant from the active site are reported. One of these crystal forms diffracted to 1.5 Å resolution and can be readily used for soaking experiments to determine high-resolution structures of IDO1 in complex with the substrate tryptophan or inhibitors that coordinate the heme. In addition, this mutant was used to produce crystals of a complex with an inhibitor that targets the apo form of the enzyme under the same conditions; the structure of this complex was determined at 1.7 Å resolution. Overall, this mutant represents a robust platform for determining the structures of inhibitor and substrate complexes of IDO1 at high resolution.


2011 ◽  
Vol 286 (44) ◽  
pp. 38691-38702 ◽  
Author(s):  
Ryota Hashizume ◽  
Yukiko Maki ◽  
Kimihiko Mizutani ◽  
Nobuyuki Takahashi ◽  
Hiroyuki Matsubara ◽  
...  

Author(s):  
Marta K. Dudek ◽  
Piotr Paluch ◽  
Edyta Pindelska

This work presents the crystal structure determination of two elusive polymorphs of furazidin, an antibacterial agent, employing a combination of crystal structure prediction (CSP) calculations and an NMR crystallography approach. Two previously uncharacterized neat crystal forms, one of which has two symmetry-independent molecules (form I), whereas the other one is a Z′ = 1 polymorph (form II), crystallize in P21/c and P 1 space groups, respectively, and both are built by different conformers, displaying different intermolecular interactions. It is demonstrated that the usage of either CSP or NMR crystallography alone is insufficient to successfully elucidate the above-mentioned crystal structures, especially in the case of the Z′ = 2 polymorph. In addition, cases of serendipitous agreement in terms of 1H or 13C NMR data obtained for the CSP-generated crystal structures different from the ones observed in the laboratory (false-positive matches) are analyzed and described. While for the majority of analyzed crystal structures the obtained agreement with the NMR experiment is indicative of some structural features in common with the experimental structure, the mentioned serendipity observed in exceptional cases points to the necessity of caution when using an NMR crystallography approach in crystal structure determination.


2017 ◽  
Vol 2017 ◽  
pp. 1-14
Author(s):  
Mayra Rodríguez-Rodríguez ◽  
Rafael Herrera-Esparza ◽  
Juan-José Bollain y Goytia ◽  
María-Elena Pérez-Pérez ◽  
Deyanira Pacheco-Tovar ◽  
...  

The goal of the present study was to determine whether peptidylarginine deiminase PAD2 and PAD4 enzymes are present in Balb/c mouse salivary glands and whether they are able to citrullinate Ro and La ribonucleoproteins. Salivary glands from Balb/c mice were cultured in DMEM and supplemented with one of the following stimulants: ATP, LPS, TNF, IFNγ, or IL-6. A control group without stimulant was also evaluated. PAD2, PAD4, citrullinated peptides, Ro60, and La were detected by immunohistochemistry and double immunofluorescence. PAD2 and PAD4 mRNAs and protein expression were detected by qPCR and Western blot analysis. PAD activity was assessed using an antigen capture enzyme-linked immunosorbent assay. LPS, ATP, and TNF triggered PAD2 and PAD4 expression; in contrast, no expression was detected in the control group (p<0.001). PAD transcription slightly increased in response to stimulation. Additionally, PAD2/4 activity modified the arginine residues of a reporter protein (fibrinogen) in vitro. PADs citrullinated Ro60 and La ribonucleoproteins in vivo. Molecular stimulants induced apoptosis in ductal cells and the externalization of Ro60 and La ribonucleoproteins onto apoptotic membranes. PAD enzymes citrullinate Ro and La ribonucleoproteins, and this experimental approach may facilitate our understanding of the role of posttranslational modifications in the pathophysiology of Sjögren’s syndrome.


Author(s):  
Jiabin Gao ◽  
Mohan M. Bhadbhade ◽  
Roger Bishop

Racemic 2,4,6,8-tetracarbomethoxybicyclo[3.3.0]octa-2,6-diene-3,7-diol, C16H18O10(1), was known previously to yield two solvent-free polymorphs and also a clathrate inclusion crystal form. Crystallization of (1) yields two inclusion compounds containing tetrahydrofuran (THF): (1)4·THF is obtained from a mixture of THF and methanol, whereas (1)2·THF is obtained from pure THF. The X-ray crystal structures reveal that the two compounds are extremely similar and that their host arrangements are essentially identical. They differ, however, in the proportion, orientation and host–guest interaction of the included THF molecules. The disordered guest molecules in (1)4·THF are oriented along the guest channel direction, whereas in (1)2·THF they lie across the channel. This unusual solvent–guest control of inclusion structures has implications relating to the formation of polymorphic structures and other competing crystal forms.


2017 ◽  
Vol 73 (11) ◽  
pp. 860-876 ◽  
Author(s):  
Matti F. Pronker ◽  
Roderick P. Tas ◽  
Hedwich C. Vlieg ◽  
Bert J. C. Janssen

The Nogo Receptor (NgR) is a glycophosphatidylinositol-anchored cell-surface protein and is a receptor for three myelin-associated inhibitors of regeneration: myelin-associated glycoprotein, Nogo66 and oligodendrocyte myelin glycoprotein. In combination with different co-receptors, NgR mediates signalling that reduces neuronal plasticity. The available structures of the NgR ligand-binding leucine-rich repeat (LRR) domain have an artificial disulfide pattern owing to truncated C-terminal construct boundaries. NgR has previously been shown to self-associateviaits LRR domain, but the structural basis of this interaction remains elusive. Here, crystal structures of the NgR LRR with a longer C-terminal segment and a native disulfide pattern are presented. An additional C-terminal loop proximal to the C-terminal LRR cap is stabilized by two newly formed disulfide bonds, but is otherwise mostly unstructured in the absence of any stabilizing interactions. NgR crystallized in six unique crystal forms, three of which share a crystal-packing interface. NgR crystal-packing interfaces from all eight unique crystal forms are compared in order to explore how NgR could self-interact on the neuronal plasma membrane.


Gene ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 261-265 ◽  
Author(s):  
Kazutada Watanabe ◽  
Minoru Nomoto ◽  
Saburo Nagata ◽  
Yohjiro Itoh ◽  
Kiyoko Hikichi ◽  
...  

ChemInform ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. no-no
Author(s):  
S. C. HAWKINS ◽  
R. BISHOP ◽  
I. G. DANCE ◽  
T. LIPARI ◽  
D. C. CRAIG ◽  
...  

2010 ◽  
Vol 66 (5) ◽  
pp. 577-583 ◽  
Author(s):  
Tetsuo Takimura ◽  
Kenji Kamata ◽  
Kazuhiro Fukasawa ◽  
Hirokazu Ohsawa ◽  
Hideya Komatani ◽  
...  

Protein kinase C (PKC) plays an essential role in a wide range of cellular functions. Although crystal structures of the PKC-θ, PKC-ι and PKC-βII kinase domains have previously been determined in complexes with small-molecule inhibitors, no structure of a PKC–substrate complex has been determined. In the previously determined PKC-ι complex, residues 533–551 in the C-terminal tail were disordered. In the present study, crystal structures of the PKC-ι kinase domain in its ATP-bound and apo forms were determined at 2.1 and 2.0 Å resolution, respectively. In the ATP complex, the electron density of all of the C-terminal tail residues was well defined. In the structure, the side chain of Phe543 protrudes into the ATP-binding pocket to make van der Waals interactions with the adenine moiety of ATP; this is also observed in other AGC kinase structures such as binary and ternary substrate complexes of PKA and AKT. In addition to this interaction, the newly defined residues around the turn motif make multiple hydrogen bonds to glycine-rich-loop residues. These interactions reduce the flexibility of the glycine-rich loop, which is organized for ATP binding, and the resulting structure promotes an ATP conformation that is suitable for the subsequent phosphoryl transfer. In the case of the apo form, the structure and interaction mode of the C-terminal tail of PKC-ι are essentially identical to those of the ATP complex. These results indicate that the protein structure is pre-organized before substrate binding to PKC-ι, which is different from the case of the prototypical AGC-branch kinase PKA.


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