Gate Loop Research Articles

Dissecting the innate immune recognition of morphine and its metabolites by TLR4/MD2: an in silico simulation study.

A toll-like receptor 4/myeloid differentiation factor 2 complex (TLR4/MD2) has been identified as a non-classical opioid receptor capable of recognizing morphine isomers and activating microglia in a non-enantioselective manner. Additionally, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), the major metabolites of morphine, possess similar chemical structures but exhibit distinct effects on TLR4 signaling. However, the specific mechanisms by which morphine isomers and morphine metabolites are recognized by the innate immune receptor TLR4/MD2 are not well understood. Herein, molecular dynamics simulations were performed to dissect the molecular recognition of TLR4/MD2 with morphine isomers, M3G and M6G. Morphine and its (+)-enantiomer, dextro-morphine ((+)-morphine), were found to have comparable binding free energies as well as similar interaction modes when interacting with (TLR4/MD2)2. Binding with morphine and (+)-morphine caused the motion of the F126 loop towards the inside of the MD2 cavity, which stabilizes (TLR4/MD2)2 with similar dimerization interfaces. The binding free energies of M3G and M6G with (TLR4/MD2)2, while lower than those of morphine isomers, were comparable to each other. However, the binding behaviors of M3G and M6G exhibited contrasting patterns when interacting with (TLR4/MD2)2. The glucuronide group of M3G bound to the gating loop of MD2 and formed strong interactions with TLR4*, which stabilizes the active heterotetrameric complex. In contrast, M6G was situated in cavity A of MD2, where the critical interactions between M6G and the residues of TLR4* were lost, resulting in fluctuation of (TLR4/MD2)2 away from the active conformation. These results indicate that the pivotal interactions at the dimerization interface between MD2 and TLR4* in M6G-bound (TLR4/MD2)2 were considerably weaker than those in M3G-bound (TLR4/MD2)2, which partially explains why M6G fails to activate TLR4 signaling. The discoveries from this study will offer valuable insights for the advancement of next-generation TLR4 small molecule modulators based on opioids.

Production of various phenolic aldehyde compounds using the 4CL-FCHL biosynthesis platform

Vanillin (3-methoxy-4-hydroxybenzaldehyde) is one of the most important flavoring substances used in the cosmetic and food industries. Feruloyl-CoA hydratase/lyase (FCHL) is an enzyme that catalyzes the production of vanillin from feruloyl-CoA. In this study, we report kinetic parameters and biochemical properties of FCHL from Sphingomonas paucimobilis SYK-6 (SpFCHL). Also, the crystal structures of an apo-form of SpFCHL and two complexed forms with acetyl-CoA and vanillin/CoA was present. Comparing the apo structure to its complexed forms of SpFCHL, a gate loop with an “open and closed” role was observed at the entrance of the substrate-binding site. With vanillin and CoA complexed to SpFCHL, we captured a conformational change in the feruloyl moiety-binding pocket that repositions the catalytic SpFCHLE146 and other key residues. This binding pocket does not tightly fit the vanillin structure, suggesting substrate promiscuity of this enzyme. This observation is in good agreement with assay results for phenylpropanoid-CoAs and indicates important physicochemical properties of the substrate for the hydratase/lyase reaction mechanism. In addition, we showed that various phenolic aldehydes could be produced using the 4CL-FCHL biosynthesis platform.

Characterization of a Bare-Die SiC-Based, Wirebond-Less, Integrated Half-Bridge With Multi-Functional Bus-Bars

This article presents detailed analysis and charact- erization results of a bare-die silicon carbide (SiC) MOSFET-based, half-bridge switch module with integrated decoupling capacitors and gate-driver circuitry, suitable for high-performance power electronics in applications such as next-generation automotive systems. The module structure enables wirebond-less integration in an entirely PCB-based assembly, featuring compact vertical power and gate loops with low parasitic elements. The assembly uses thermoelectrically multi-functional components, which simultaneously serves as busbars and heat sinks, thereby obviating the need for thermal interface material, and also allows quasi-double-sided cooling. This article starts with a comprehensive review of integrated power modules followed by a description of the module structure under consideration and its various practical design aspects. Thereafter, a detailed discussion is presented on electrical parasitic modeling, conducted using 3-D finite element analysis simulations in Ansys Q3D. Results indicate that the module can achieve extremely low values of loop inductances ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{\mathrm{ loop,power}}$ </tex-math></inline-formula> = 1.35 nH and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{\mathrm{ loop,gate}}$ </tex-math></inline-formula> = 5.1 nH at an oscillation frequency of 100 MHz) without entailing high parasitic capacitances, which can provide enhanced switching performance compared with state-of-the-art solutions. Experiments performed on a proof-of-concept half-bridge prototype, operated up to 600 V, 30 A demonstrate close adherence of the measured electrical parameters with theoretical predictions and acceptable preliminary thermal performance.

Craspase is a CRISPR RNA-guided, RNA-activated protease.

The CRISPR-Cas type III-E RNA-targeting effector complex gRAMP/Cas7-11 is associated with a caspase-like protein (TPR-CHAT/Csx29) to form Craspase (CRISPR-guided caspase). Here, we use cryo-electron microscopy snapshots of Craspase to explain its target RNA cleavage and protease activation mechanisms. Target-guide pairing extending into the 5' region of the guide RNA displaces a gating loop in gRAMP, which triggers an extensive conformational relay that allosterically aligns the protease catalytic dyad and opens an amino acid side-chain-binding pocket. We further define Csx30 as the endogenous protein substrate that is site-specifically proteolyzed by RNA-activated Craspase. This protease activity is switched off by target RNA cleavage by gRAMP and is not activated by RNA targets containing a matching protospacer flanking sequence. We thus conclude that Craspase is a target RNA-activated protease with self-regulatory capacity.

Structural investigation of pathogenic variants in dihydropyrimidinase using molecular dynamics simulations

Dihydropyrimidinase (DHP) is an enzyme that catabolizes the degradation of pyrimidine and fluoropyrimidine drugs such as 5-fluorouracil. DHP deficiency triggers various clinical symptoms and increases the risk of fluoropyrimidine drug toxicity. Various pathogenic variants of DHP cause DHP deficiency, and their catalytic activities have been well studied. However, the three-dimensional structures of DHP variants have not been clarified. In this study, we investigated the effects of mutations on DHP structures using the molecular dynamics simulations. Simulations of the wild type and 10 variants were performed and compared. In the T68R, D81G, G278D, and L337P variants, the flexibilities of structures related to the interaction for oligomer formation increased in comparison with those of the wild type. W117R, T343A, and R412 M mutations affected the structures of stereochemistry gate loops or the substrate-binding pocket. The three-dimensional structures of W360R and G435R variants were suggested to collapse. On the other hand, only slight structural changes were observed in the R181W variant, whose experimentally observed activity was similar to that of the wild type. The computational results are expected to clarify the relationship between clinical mutations and structural effects of drug-metabolizing enzymes.

Comparison of GaN Enhancement Mode Transistor Performance With Integrated and External Driver

GaN components allow to reduce power losses as the lower specific on-resistance and higher switching speeds reduce both the conduction and switching loss. However, parasitics in the gate loop cause ringing which endangers the component. To counteract these problems the switching speed is lowered renouncing part of the components superior performance. A possible way to avoid gate loop parasitics and make circuit design less challenging is integrating the driver in the same package with the GaN transistor. In this paper the performance of an integrated driver with enhancement mode GaN half-bridge that is monolithically integrated using IMEC GaN-on-SOI will be tested in a synchronous boost converter setup. Converter efficiency and switching waveforms will be reported together with a comparison to a GaN half-bridge with external drivers. The converter is tested at input voltages up to 50 V and powers up to 100 W. Package temperature measurements are included to estimate the influence of the temperature dependent on-resistance on the results. At the end of the paper, a sensitivity analysis is conducted to quantify the behaviour of the losses in function of different input parameters including a measurement at switching frequencies up to 1MHz.

Influence of parasitic coupling on current sharing in paralleled SiC MOSFET devices

This paper comprehensively investigates the current distribution behaviours of paralleled SiC MOSFET devices under the parasitic coupling between gate and power loops. Three types of connection that are commonly adopted in actual applications, comprising common source connection (CSC), Kelvin source connection (KSC) and hybrid source connection (HSC), are thoroughly discussed. The influence mechanism of mismatch in values for three parasitic inductances on current sharing during different switching periods is studied in theory. Simulations and experiments are also carried out and results are used to validate the theoretical analysis. Parasitic capacitance, common source and quasi common source parasitic inductance couplings are the three main coupling modes between gate loop and power loop in a circuit with paralleled SiC MOSFETs. The current imbalance is mainly due to the variation of gate-source voltage generated by the mismatch in the parasitic inductances through the three coupling paths. This paper aims to provide an insight into current sharing mechanism of paralleled devices with circuit parasitic mismatches. Influence of every parasitic inductance under each of the three coupling modes is investigated and recommendation made on choice of coupling mode and viable switching speed and current balance tradeoff that can be adopted in a practical system design.

Review of the designs in low inductance SiC half‐bridge packaging

Silicon carbide (SiC) device has become the primary choice for high-efficiency power electronic equipment due to its excellent performance. However, its higher switching frequency and faster switching speed have also incurred new challenges, such as low parasitic inductance packaging. Despite a significant amount of literature to overview the low parasitic inductance packages, most of them focus on total parasitic inductance from different packaging technology. Here, from the viewpoint of partial inductance which includes gate loop, power loop and common source, the designs for different inductances are surveyed. The power loop is further discussed from power terminals, bonding wires and direct bonded copper (DBC) conductor traces. The effects and sources of these inductances are analyzed. Furthermore, the typical design solutions to reduce the inductances are summarized. Finally, the challenges of SiC packages are presented.

The Y\u03a6 motif defines the structure-activity relationships of human 20S proteasome activators

The 20S proteasome (20S) facilitates turnover of most eukaryotic proteins. Substrate entry into the 20S first requires opening of gating loops through binding of HbYX motifs that are present at the C-termini of certain proteasome activators (PAs). The HbYX motif has been predominantly characterized in the archaeal 20S, whereas little is known about the sequence preferences of the human 20S (h20S). Here, we synthesize and screen ~120 HbYX-like peptides, revealing unexpected differences from the archaeal system and defining the h20S recognition sequence as the Y-F/Y (YФ) motif. To gain further insight, we create a functional chimera of the optimized sequence, NLSYYT, fused to the model activator, PA26E102A. A cryo-EM structure of PA26E102A-h20S is used to identify key interactions, including non-canonical contacts and gate-opening mechanisms. Finally, we demonstrate that the YФ sequence preferences are tuned by valency, allowing multivalent PAs to sample greater sequence space. These results expand the model for termini-mediated gating and provide a template for the design of h20S activators.

Dynamic assembly of the mRNA m6A methyltransferase complex is regulated by METTL3 phase separation.

m6A methylation is the most abundant and reversible chemical modification on mRNA with approximately one-fourth of eukaryotic mRNAs harboring at least one m6A-modified base. The recruitment of the mRNA m6A methyltransferase writer complex to phase-separated nuclear speckles is likely to be crucial in its regulation; however, control over the activity of the complex remains unclear. Supported by our observation that a core catalytic subunit of the methyltransferase complex, METTL3, is endogenously colocalized within nuclear speckles as well as in noncolocalized puncta, we tracked the components of the complex with a Cry2-METTL3 fusion construct to disentangle key domains and interactions necessary for the phase separation of METTL3. METTL3 is capable of self-interaction and likely provides the multivalency to drive condensation. Condensates in cells necessarily contain myriad components, each with partition coefficients that establish an entropic barrier that can regulate entry into the condensate. In this regard, we found that, in contrast to the constitutive binding of METTL14 to METTL3 in both the diffuse and the dense phase, WTAP only interacts with METTL3 in dense phase and thereby distinguishes METTL3/METTL14 single complexes in the dilute phase from METTL3/METTL14 multicomponent condensates. Finally, control over METTL3/METTL14 condensation is determined by its small molecule cofactor, S-adenosylmethionine (SAM), which regulates conformations of two gate loops, and some cancer-associated mutations near gate loops can impair METTL3 condensation. Therefore, the link between SAM binding and the control of writer complex phase state suggests that the regulation of its phase state is a potentially critical facet of its functional regulation.

A Compact Double-Sided Cooling 650V/30A GaN Power Module With Low Parasitic Parameters

Compared with silicon and silicon carbide devices, the unique electrical and structural characteristics of gallium nitride high electron mobility transistors (GaN HEMTs) make them have different requirements for power module integration. This article proposes a novel integration scheme for the high-voltage lateral GaN HEMT dies without bonding wires. Based on the proposed integration scheme, a compact 650 V/30 A GaN power module with low parasitic parameters and high thermal performance is designed. The GaN dies are sandwiched between two ceramic substrates to improve thermal performance and ensure consistent thermal expansion coefficients. The multiple copper layer structure is used to increase wiring flexibility to reduce parasitic parameters. The design of gate and power loop layouts is discussed, and the common-mode (CM) capacitance is optimized. A comprehensive reliability evaluation is also carried out for this integration scheme. Finally, a double-sided cooling 650 V/30 A full-bridge GaN power module with 2.4 cm×1.3 cm×0.17 cm is fabricated. The thermal resistance is reduced by 30%–48% compared with the conventional single-sided cooling module. The power loop and gate loop inductances are reduced to 0.94 nH and 2 nH, respectively, and the CM capacitance is limited to 2.5 pF. The maximum d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</i> /d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</i> of the drain–source voltage is high as 150 V/ns with only 10% overshoot. Based on the power module, a 3.3-kW two-phase interleaved buck converter is developed. It has 820 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> power density and 98.85% peak efficiency.

Research on deep learning method of intrusion attack prediction in software defined network

At present, with the increase of the number of network attacks, in the software defined network, the controller is equivalent to the brain, which is an entity with a complete view of the network. When the attacker directs the malicious traffic to the controller, it may lead to the paralysis of the whole network. Therefore, although there are many solutions for intrusion detection, the attack prediction of network intrusion is still a problem worthy of study. This paper proposes a deep learning model based on gating loop unit (Gru) to identify and prevent intrusion attacks. The model can deeply learn the dependencies of security alarm sequences, and use data sets to evaluate the model. Experiments show that it can show the significant improvement of attack detection.

Computational Insights Into the Effects of the R190K and N121Q Mutations on the SARS-CoV-2 Spike Complex With Biliverdin.

The SARS-CoV-2 spike has been regarded as the main target of antibody design against COVID-19. Two single-site mutations, R190K and N121Q, were deemed to weaken the binding affinity of biliverdin although the underlying molecular mechanism is still unknown. Meanwhile, the effect of the two mutations on the conformational changes of “lip” and “gate” loops was also elusive. Thus, molecular dynamics simulation and molecular mechanics/generalized Born surface area (MM/GBSA) free energy calculation were conducted on the wild-type and two other SARS-CoV-2 spike mutants. Our simulations indicated that the R190K mutation causes Lys190 to form six hydrogen bonds, guided by Asn99 and Ile101, which brings Lys190 closer to Arg102 and Asn121, thereby weakening the interaction energy between biliverdin and Ile101 as well as Lys190. For the N121Q mutation, Gln121 still maintained a hydrogen bond with biliverdin; nevertheless, the overall binding mode deviated significantly under the reversal of the side chain of Phe175. Moreover, the two mutants would stabilize the lip loop, which would restrain the meaningful upward movement of the lip. In addition, N121Q significantly promoted the gate loop deviating to the biliverdin binding site and compressed the site. This work would be useful in understanding the dynamics binding biliverdin to the SARS-CoV-2 spike.

The ABA receptor gene MdPYL9 confers tolerance to drought stress in transgenic apple (Malus domestica)

Abscisic acid (ABA) is an important phytohormone for plant growth, development, and the response to various types of abiotic stress. Pyrabactin Resistance 1 (PYR1)/PYR1-Like (PYL)/Regulatory Component of ABA Receptor (RCAR) family proteins (PYLs) are ABA receptors that have been studied in many plant species. However, no detailed functional studies of these genes in regulating apple drought tolerance have been reported. Here, we isolated a homolog of the ABA receptor PYL9 in Arabidopsis, MdPYL9, from apple (Malus domestica) and analyzed its role in regulating drought tolerance in transgenic apple plants. Gene structure and protein sequence analysis showed that MdPYL9 shares a high similarity with AtPYL9. Protein sequence comparison and 3D structure prediction identified several conserved motifs and residues that are important for ABA binding in MdPYL9, including the helix-grip structure and the gate and latch loops. Expression analysis showed that MdPYL9 was significantly induced by drought treatment. Overexpression of MdPYL9 conferred enhanced tolerance to drought stress in transgenic apple plants, including a higher photosynthetic rate and relative water content and lower MDA content and electrolyte leakage compared with wild-type plants. Lower accumulation of reactive oxygen species (ROS) and higher activity of antioxidant enzymes suggest that MdPYL9 overexpression could promote ROS scavenging and thus reduce oxidative damage in transgenic apple plants under drought stress. Yeast two-hybrid assays indicated that there were both ABA-dependent and ABA-independent interactions between MdPYL9 and the clade A subgroup members of the PP2C family (PP2CAs) in apple. Expression analysis identifed two PP2CA genes, MdHAI1 and MdHAI2, that were highly expressed under drought treatment by not expressed under normal conditions. These results provide new insight that could be used to aid future studies examining the function of MdPYLs and the mechanism by which they regulate apple drought tolerance.

Phenotypic effects of changes in the FTVTxK region of an Arabidopsis secondary wall cellulose synthase compared with results from analogous mutations in other isoforms.

Understanding protein structure and function relationships in cellulose synthase (CesA), including divergent isomers, is an important goal. Here, we report results from mutant complementation assays that tested the ability of sequence variants of AtCesA7, a secondary wall CesA of Arabidopsis thaliana, to rescue the collapsed vessels, short stems, and low cellulose content of the irx3-1 AtCesA7 null mutant. We tested a catalytic null mutation and seven missense or small domain changes in and near the AtCesA7 FTVTSK motif, which lies near the catalytic domain and may, analogously to bacterial CesA, exist within a substrate "gating loop." A low-to-high gradient of rescue occurred, and even inactive AtCesA7 had a small positive effect on stem cellulose content but not stem elongation. Overall, secondary wall cellulose content and stem length were moderately correlated, but the results were consistent with threshold amounts of cellulose supporting particular developmental processes. Vibrational sum frequency generation microscopy allowed tissue-specific analysis of cellulose content in stem xylem and interfascicular fibers, revealing subtle differences between selected genotypes that correlated with the extent of rescue of the collapsing xylem phenotype. Similar tests on PpCesA5 from the moss Physcomitrium (formerly Physcomitrella) patens helped us to synergize the AtCesA7 results with prior results on AtCesA1 and PpCesA5. The cumulative results show that the FTVTxK region is important for the function of an angiosperm secondary wall CesA as well as widely divergent primary wall CesAs, while differences in complementation results between isomers may reflect functional differences that can be explored in further work.

Complicated human action understanding by massive-scale graph discovering technique

In order to solve the problem that the first frame of human motion prediction is discontinuous, we notice that the prediction time is short due to the influence of uncertain factors such as motion speed and motion amplitude. In this work, an end-to-end model based on bidirectional gating loop unit (GRU) and attention mechanism, biagru-seq2seq, is proposed. The encoder of our deep model adopts bidirectional Gru structure to input data from both positive and negative directions simultaneously. Meanwhile, the decoder part adopts unidirectional GRU structure and adds attention mechanism to encode the output of the encoder into a vector sequence containing multiple subsets. Also, a large-scale graph discovery framework is used to identify the various human action components. Subsequently, the input and output data of the decoder are fed into the residual at the same time. In the designed tensorflow framework, we use human3.6m, the largest open data set of motion capture data at present, to fulfill human motion prediction applications. Comprehensive experimental results have shown that the proposed model can not only substantially reduce the short-term motion prediction error, but also accurately predict multi frame human action recognition.

SARS-CoV-2 can recruit a heme metabolite to evade antibody immunity.

The coronaviral spike is the dominant viral antigen and the target of neutralizing antibodies. We show that SARS-CoV-2 spike binds biliverdin and bilirubin, the tetrapyrrole products of heme metabolism, with nanomolar affinity. Using cryo-electron microscopy and x-ray crystallography, we mapped the tetrapyrrole interaction pocket to a deep cleft on the spike N-terminal domain (NTD). At physiological concentrations, biliverdin significantly dampened the reactivity of SARS-CoV-2 spike with immune sera and inhibited a subset of neutralizing antibodies. Access to the tetrapyrrole-sensitive epitope is gated by a flexible loop on the distal face of the NTD. Accompanied by profound conformational changes in the NTD, antibody binding requires relocation of the gating loop, which folds into the cleft vacated by the metabolite. Our results indicate that SARS-CoV-2 spike NTD harbors a dominant epitope, access to which can be controlled by an allosteric mechanism that is regulated through recruitment of a metabolite.

Natural Product Inhibition and Enzyme Kinetics Related to Phylogenetic Characterization for Bacterial Peptidyl-tRNA Hydrolase 1.

With the relentless development of drug resistance and re-emergence of many pathogenic bacteria, the need for new antibiotics and new antibiotic targets is urgent and growing. Bacterial peptidyl-tRNA hydrolase, Pth1, is emerging as a promising new target for antibiotic development. From the conserved core and high degree of structural similarity, broad-spectrum inhibition is postulated. However, Pth1 small-molecule inhibition is still in the earliest stages. Focusing on pathogenic bacteria, herein we report the phylogenetic classification of Pth1 and natural product inhibition spanning phylogenetic space. While broad-spectrum inhibition is found, narrow-spectrum and even potentially clade-specific inhibition is more frequently observed. Additionally reported are enzyme kinetics and general in vitro Pth1 solubility that follow phylogenetic boundaries along with identification of key residues in the gate loop region that appear to govern both. The studies presented here demonstrate the sizeable potential for small-molecule inhibition of Pth1, improve understanding of Pth enzymes, and advance Pth1 as a much-needed novel antibiotic target.

Tuning Protein Discrimination Through Altering the Sampling Interface Formed between the Analyte and the OmpG Nanopore.

Nanopore sensors capable of distinguishing homologous protein analytes are highly desirable tools for proteomics research and disease diagnostics. Recently, an engineered outer membrane protein G (OmpG) nanopore with a high-affinity ligand attached to a gating loop 6 showed specificity for distinguishing homologous proteins in complex mixtures. Here, we report the development of OmpG nanopores with the other six loops used as the anchoring point to host an affinity ligand for protein sensing. We investigated how the analyte binding to the affinity ligand located at different loops affects the detection sensitivity, selectivity, and specificity. Our results reveal that analytes weakly attracted to the OmpG nanopore surface are only detectable when the ligand is tethered to loop 6. In contrast, protein analytes that form a strong interaction with the OmpG surface via electrostatic attractions are distinguishable by all seven OmpG nanopore constructs. In addition, the same analyte can generate distinct binding signals with different OmpG nanopore constructs. The ability to exploit all seven OmpG loops will aid the design of a new generation of OmpG sensors with increased sensitivity, selectivity, and specificity for biomarker sensing.

Analysis and Suppression of High Speed Dv/Dt Induced False Turn-on in GaN HEMT Phase-Leg Topology

Gallium nitride high electron mobility transistor (GaN HEMT) is liable to gate false turn-on problem when the gate crosstalk voltage exceeds its threshold voltage in the widely adopted phase-leg topology due to its low threshold voltage and high switching speed. Without considering the gate loop stray inductance, gate internal resistance, nonlinearity of parasitic capacitances and power loop stray parameters, traditional false turn-on analytical method is insufficient to support accurate analysis. And it has been found that GaN HEMT gate-source parasitic capacitance C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> previously assumed constant is otherwise highly nonlinear and has strong impacts on the gate crosstalk voltage. This paper has measured C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> by vector network analyzer and constructed an accurate nonlinear model of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> , based on which an accurate GaN HEMT behavior model is further fulfilled. The accuracy of the proposed behavior model has been verified by large amounts of experiment results. The proposed GaN HEMT model is used to accurately calculate gate crosstalk voltage and switching losses. Besides, false turn-on induced extra loss has been calculated and is adopted as a criterion to evaluate the severity of false turn-on and optimal design method for false turn-on suppression has been detailed further.