Residues important to the allosteric regulation on ligand binding affinity in β3 integrins

Integrins are heterodimers that mediate cell adhesion and transduce signals bidirectionally across the cell membrane.Integrins often exist in low affinity(or inactive) states for

The zinc-finger protein ZFYVE1 modulates TLR3-mediated signaling by facilitating TLR3 ligand binding

Recognition of viral dsRNA by Toll-like receptor 3(TLR3)leads to the induction of downstream antiviral effectors and the innate antiviral immune response.Here,we identified the zinc-finger FYVE domain-containing protein ZFYVE1,a guanylate-binding protein(GBP),as a positive regulator of TLR3-mediated signaling.Overexpression of ZFYVE1 promoted the transcription of downstream antiviral genes upon stimulation with the synthetic TLR3 ligand poly(I:C).Conversely,ZFYVE1 deficiency had the opposite effect.Zfyve1^(−/−) mice were less susceptible than wild-type mice to inflammatory death induced by poly(I:C)but not LPS.ZFYVE1 was associated with TLR3,and the FYVE domain of ZFYVE1 and the ectodomain of TLR3 were shown to be responsible for their interaction.ZFYVE1 was bound to poly(I:C)and increased the binding affinity of TLR3 to poly(I:C).These findings suggest that ZFYVE1 plays an important role in the TLR3-mediated innate immune and inflammatory responses by promoting the ligand binding of TLR3.

Comparison of ligand migration and binding in heme proteins of the globin family

The binding of small diatomic ligands such as carbon monoxide or dioxygen to heme proteins is among the simplest biological processes known. Still, it has taken many decades to understand the mechanistic aspects of this process in full detail. Here, we compare ligand binding in three heme proteins of the globin family, myoglobin, a dimeric hemoglobin, and neuroglobin. The combination of structural, spectroscopic, and kinetic experiments over many years by many laboratories has revealed common properties of globins and a clear mechanistic picture of ligand binding at the molecular level. In addition to the ligand binding site at the heme iron, a primary ligand docking site exists that ensures efficient ligand binding to and release from the heme iron. Additional, secondary docking sites can greatly facilitate ligand escape after its dissociation from the heme. Although there is only indirect evidence at present, a preformed histidine gate appears to exist that allows ligand entry to and exit from the active site. The importance of these features can be assessed by studies involving modified proteins（via site-directed mutagenesis） and comparison with heme proteins not belonging to the globin family.

A computational study of the chemokine receptor CXCR1 bound with interleukin-8

CXCR1 is a G-protein coupled receptor, transducing signals from chemokines, in particular the interleukin-8 （1L8） molecules. This study combines homology modeling and molecular dynamics simulation methods to study the structure of CXCRI-IL8 complex. By using CXCR4-vMIP-II crystallography structure as the homologous template, CXCRI-IL8 complex structure was constructed, and then refined using all-atom molecular dynamics simulations. Through extensive simulations, CXCRI-IL8 binding poses were investigated in detail. Furthermore, the role of the N-terminal of CXCR1 receptor was studied by comparing four complex models differing in the N-terminal sequences. The results indicate that the receptor N-terminal affects the binding of IL8 significantly. With a shorter N-terminal domain, the binding of IL8 to CXCR1 becomes unstable. The homology modeling and simulations also reveal the key receptor-ligand residues involved in the electrostatic interactions known to be vital for complex formation.

Therapeutic targeting of the androgen receptor(AR)and AR variants in prostate cancer

Prostate cancer(PCa)accounted for over 300000 deaths world-wide in 2018.Most of the PCa deaths occurred due to the aggressive castration-resistant PCa(CRPC).Since the androgen receptor(AR)and its ligands contribute to the continued growth of androgendependent PCa(ADPCa)and CRPC,AR has become a well-characterized and pivotal therapeutic-target.Although AR signaling was identified as therapeutic-target in PCa over five-decades ago,there remains several practical issues such as lack of antagonist-bound AR crystal structure,stabilization of the AR in the presence of agonists due to N-terminus and C-terminus interaction,unfavorable large-molecule accommodation of the ligand-binding domain(LBD),and generation of AR splice variants that lack the LBD that impede the discovery of highly potent fail-safe drugs.This review summarizes the AR-signaling pathway targeted therapeutics currently used in PCa and the approaches that could be used in future ARtargeted drug development of potent next-generation molecules.The review also outlines the discovery of molecules that bind to domains other than the LBD and those that inhibit both the full length and splice variant of ARs.

Structure-based function prediction of the expanding mollusk tyrosinase family

Tyrosinase （Ty） is a common enzyme found in many different animal groups. In our previous study, genome sequencing revealed that the Ty family is expanded in the Pacific oyster （Crassostrea gigas）. Here, we examine the larger number of Ty family members in the Pacific oyster by high-level structure prediction to obtain more information about their function and evolution, especially the unknown role in biomineralization. We verified 12 Ty gene sequences from Crassostrea gigas genome and Pinctadafucata martensii transcriptome. By using phylogenetic analysis of these Tys with functionally known Tys from other molluscan species, eight subgroups were identified （CgTy_sl, CgTy s2, MolTy sl, MolTy-s2, MolTy-s3, PinTy-s 1, PinTy-s2 and PviTy）. Structural data and surface pockets of the dinuclear copper center in the eight subgroups of molluscan Ty were obtained using the latest versions of prediction online servers. Structural comparison with other Ty proteins from the protein databank revealed functionally important residues （HA1, HA2, HA3, HB1, HB2, HB3, Z l-Z9） and their location within these protein structures. The structural and chemical features of these pockets which may related to the substrate binding showed considerable variability among mollusks, which undoubtedly defines Ty substrate binding. Finally, we discuss the potential driving forces of Ty family evolution in mollusks. Based on these observations, we conclude that the Ty family has rapidly evolved as a consequence of substrate adaptation in mollusks.

Natural products and their derivatives as G-quadruplex binding ligands

G-quadruplexes comprise a class of secondary structures that are formed in guanine-rich sequences in eukaryotic genomes and play a crucial role in the regulation of many biological events.G-quadruplexes have become targets for anticancer drugs with high selectivity vs.duplex DNA and low cytotoxicity against normal cells.Natural products and their derivatives display polymorphism,structural complexity,and potent activity.It is,therefore,reasonable to seek ligands targeting G-quadruplexes from natural products.Recently,many successful examples have been reported,showing ligands with excellent anticancer activities.In this review,we summarized the development of research on natural products and derivatives that target G-quadruplex structures in an effort to guide future studies.

Binding of Cry δ-endotoxins to brush border membrane vesicles of Helicoverpa armigera and Helicoverpa punctigera （Lepidoptera： Noctuidae）

The relatively low susceptibility ofHelicoverpa armigera to CrylAc, its history of resistance to chemical insecticides and the seasonal decline in expression of CrylAc in transgenic cotton necessitated the development of cotton expressing two insecticidal proteins to provide sustainable control of this multinational pest. To manage the resistance issue, it was essential that the second insecticidal protein have a significantly different mode of action to CrylAc. A common feature of resistance to CrylA proteins in several species as well as H. armigera has been a change in the binding site. A study of binding sites for some Cry proteins in the brush border membrane vesicles （BBMV） ofH. armigera and Helicoverpa punctigera was undertaken. The binding affinity for CrylAc was higher than for CrylAb, matching their relative toxicities, and CrylAc and CrylAb were found to share at least one binding site in both I-1. armigera and I-1. punctigera. However Cry2Aa did not compete with CrylAc for binding and so could be used in transgenic cotton in combination with CrylAc to control H. armigera and manage resistance. Variation in the susceptibilities of three different H. armigera strains to CrylAc correlated with the parameter Bmax/Kcom.

Molecular and functional analysis of monoclonal antibodies in support of biologics development

Monoclonal antibody （mAb）-based therapeutics are playing an increasingly important role in the treatment or pre- vention of many important diseases such as cancers, autoimmune disorders, and infectious diseases. Multi- domain mAbs are far more complex than small molecule drugs with intrinsic heterogeneities. The critical quality attributes of a given mAb, including structure, post-trans- lational modifications, and functions at biomolecular and cellular levels, need to be defined and profiled in details during the developmental phases of a biologics. These critical quality attributes, outlined in this review, serve an important database for defining the drug properties during commercial production phase as well as post licensure life cycle managemenL Specially, the molecular characteriza- tion, functional assessment, and effector function analysis of mAbs, are reviewed with respect to the critical parame- ters and the methods used for obtaining them. The three groups of analytical methods are three essential and inte. gral facets making up the whole analytical package for a mAIPbased drug. Such a package is critically important for the licensure and the post-licensurs life cycle management of a therapeutic or prophylactic biologics. In addition, the basic principles on the evaluation of biosimilar mAbs were discussed briefly based on the recommendations by the World Health Organization.

EffectofElectroacupunctureonPulmonaryβ－AdrenoceptorinAllergicAsthmaGuinea－Pigs

Twenty four male guinea-pigs were randomly divided into 3 groups: Group A, allergic asthmaguinea-pigs prepared by peritoneal injection and spraying inhalation of albumin; Group B, allergic asthmaguinea-pigs treated with electroacupuncture through stimulating the acupoint Feishu (UB13 ) and Group C, thecontrol group. With[3H] -DHA as a radioligand, pulmonary adrenoceptor ( AC) in the 3 groups of guinea-pigs were detrermined by radioligand binding assay technique. The results showed that: ( 1 ) The maximumbinding volume of receptor ligand ( Bmax, fmol/mg prot. ) of pulmonary AC in Group A (123. 86 42. 91 )was significantly lower than that in group C (199 . 54 37. 03 , P< 0. 05) , while the difference between groupB ( 142. 00 42. 91 ) and group C was not significant ( P > 0. 05 ) . ( 2 ) The Kd ( nM) of pulmonary AC ingroup A, B and C were 5 . 10 1 . 39 , 6. 53 2 . 41 and 8. 72 2 . 02 respectively, and the differences amongthe three groups were not significant ( P >0. 05) . The results indicated that the decrease of the content anddysfunction of pulmonary AC in allergic asthma guinea-pigs might be regulated by electroacupuncture thera-py.