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Investigation of the structural and dynamic basis of kinesin dissociation from microtubule by atomistic molecular dynamics simulations

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Chinese Physics B 2022年第5期31卷 756-765页

作者： Jian-Gang Wang Xiao-Xuan Shi Yu-Ru Liu Peng-Ye Wang Hong Chen Ping Xie School of Material Science and Engineering Central South University of Forestry and TechnologyChangsha 410004China Key Laboratory of Soft Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Kinesin is a molecular motor that can step processively on microtubules via the hydrolysis of ATP *** important factor characterizing the processivity of the kinesin motor is its dissociation from the ***,using all-atom molecular dynamics simulations,we studied the dissociation process of the kinesin head in weak-microtubulebinding or ADP state from tubulin on the basis of the available high-resolution structural data for the head and *** analyzing the simulated snapshots of the structure of the head-tubulin complex we provided detailed structural and dynamic information for the dissociation *** found that the dissociation of the head along different directions relative to the tubulin exhibits very different dynamic ***,the potential forms or energy landscapes of the interaction between the head and tubulin along different directions were *** studies have important implications for the detailed molecular mechanism of the dissociation of the kinesin motor and thus are critical to the mechanism of its processivity.

关键词： kinesin dissociation energy landscape molecular dynamics simulation

Low-Energy Protons in Strong-Field dissociation of H_(2)^(+) via Dipole-Transitions at Large Bond Lengths

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Ultrafast Science 2022年第2期2卷 9-17页

作者： Shengzhe Pan Chenxi Hu Zhaohan Zhang Peifen Lu Chenxu Lu Lianrong Zhou Jiawei Wang Fenghao Sun Junjie Qiang Hui Li Hongcheng Ni Xiaochun Gong Feng He Jian Wu State Key Laboratory of Precision Spectroscopy East China Normal UniversityShanghai 200241China Key Laboratory for Laser Plasmas(Ministry of Education)and School of Physics and Astronomy Collaborative Innovation Center of IFSA(CICIFSA)Shanghai Jiao Tong UniversityShanghai 200240China CAS Center for Excellence in Ultra-Intense Laser Science Shanghai 201800China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuanShanxi 030006China

More than ten years ago,the observation of the low-energy structure in the photoelectron energy spectrum,regarded as an“ionization surprise,”has overthrown our understanding of strong-field ***,the similar low-energy nuclear fragment generation from dissociating molecules upon the photon energy absorption,one of the well-observed phenomena in light-molecule interaction,still lacks an unambiguous mechanism and remains ***,we introduce a time-energy-resolved manner using a multicycle near-infrared femtosecond laser pulse to identify the physical origin of the light-induced ultrafast dynamics of *** simultaneously measuring the bond-stretching times and photon numbers involved in the dissociation of H_(2)^(+) driven by a polarization-skewed laser pulse,we reveal that the low-energy protons(below 0.7 eV)are produced via dipole-transitions at large bond *** observed low-energy protons originate from strong-field dissociation of high vibrational states rather than the low ones of H_(2)^(+) cation,which is distinct from the well-accepted bond-softening *** numerical simulation of the time-dependent Schrödinger equation unveils that the electronic states are periodically distorted by the strong laser field,and the energy gap between the field-dressed transient electronic states may favor the one-or three-photon transitions at the internuclear distance larger than 5 *** time-dependent scenario and our time-energy-resolved approach presented here can be extended to other molecules to understand the complex ultrafast dynamics.

关键词： dynamics transitions dissociation

dissociation characteristics of methane hydrate using depressurization combined with thermal stimulation

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Chinese Journal of Chemical Engineering 2019年第9期27卷 2089-2098页

作者： Mingjun Yang Zhanquan Ma Yi Gao Lanlan Jiang Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology

Methane hydrate is considered as a potential energy source in the future due to its abundant reserves and high energy *** investigate the influence of initial hydrate saturation,production pressure,and the temperature of thermal stimulation on gas production rate and cumulative gas production percentage,we conducted the methane hydrate dissociation experiments using depressurization,thermal stimulation and a combination of two methods in this *** is found that when the gas production pressures are the same,the higher the hydrate initial saturation,the greater change in hydrate reservoir ***,it is easier to appear the phenomenon of icing and hydrate reformation when the hydrate saturation is *** example,the reservoir temperature dropped to below zero in depressurization process when the hydrate saturation was about 37%.However,the same phenomenon didn’t appear as the saturation was about 12%.This may be due to more free gas in the reservoir with hydrate saturated of 37%.We also find that the temperature variation of reservoir can be reduced effectively by combination of depressurization and thermal stimulation *** the average gas production rate is highest with combined method in the *** the pressure of gas production is 2 MPa,compared with depressurization,the average of gas production can increase 54%when the combined method is *** efficiency of gas production is very low when thermal stimulation was used *** the temperature of thermal stimulation is 11℃,the average rate of gas production in the experiment of thermal stimulation is less than 1/3 of that in the experiment of the combined method.

关键词： Methane hydrate Depressurization Thermal stimulation dissociation characteristics

dissociation Temperature of Strictly Confined Charmonium States

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Chinese Physics Letters 2012年第3期29卷 59-62页

作者： QU Zhen LIU Yun-Peng ZHUANG Peng-Fei Department of Physics Tsinghua UniversityBeijing 100084

We study the dissociation of strictly confined charmonium states at finite *** strict confinement constraint to the Cornell potential leads to a 10%higher J/(φ)dissociation temperature and in turn a weaker J/(φ)supp... 详细信息

关键词： temperature dissociation strictly

dissociation behavior of (CH_4+C_2H_4) hydrate in the presence of sodium dodecyl sulfate

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Petroleum Science 2010年第1期7卷 112-117页

作者： Peng Baozi Sun Changyu Chen Guangjin Tang Xulong Liu Peng Chen Jun Zhang Yanqin State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China High Pressure Fluid Phase Behavior ＆ Property Research Laboratory China University of Petroleum Beijing 102249 China

Separation of a mixture of CH4＋C2H4 gas by forming hydrate in ethylene production has become of interest, and the dissociation behavior of （CH4＋C2H4） hydrate is of great importance for this process. The hydrate formation rate could be increased by adding a small amount of sodium dodecyl sulfate （SDS） into water. In this work, the kinetic data of CH4（18.5 mol%）＋C2H4（81.5 tool%） hydrate decomposition in the presence of 1000 mg.L-~ SDS at different temperatures and pressures were measured with the depressurizing method using a sapphire cell apparatus. The experimental results show that the dissociation rate of （CH4＋C2H4） mixed gas hydrate was large at high temperature and low pressure, and temperature had great influence on the dissociation rate at high pressure. A kinetic model for hydrate dissociation was proposed and the calculated results from the kinetic model were in good agreement with the experimental data. The activation energy for dissociation of the （CH4＋C2H4） mixed gas hydrate was determined to be 43.9 kJ-mol-~, which is lower than that of methane （81.0 ***-~） and ethane （104.0 kJ＇mol-~） hydrate in water （Clarke and Bishnoi, 2004）. As the similar molecular dimensions between ethane and ethylene, the close activation energy need to be provided for ethylene hydrate dissociation. The obtained activation energy of the （CH4＋C2H4） mixed gas hydrate dissociation indicates that the dissociation of the （CH4＋C2H4） mixed gas hydrate is easier than that of pure CH4 or C2H4 gas hydrate.

关键词： Methane ethylene hydrate dissociation SDS

dissociation of CO on Oxygen Contaminated Ni{001}c(2×2)-Al Surface at Room Temperature

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Chinese Physics Letters 1991年第1期8卷 17-20页

作者： YAO Jun ZHU Li LU Sihua WU Sicheng Synchrotron Radiation Laboratoryf Institute of High Energy Physics Academia SinicaBeijing 100039 Department of Physics Zhejiang UniversityHangzhou 310027 Department of PhysicSj Peking University Beijing 100871 Laboratory For Surface Physics Academia SinicaBeijing 100080

The dissociation of CO on oxygen contaminated Ni{001}c(2×2)-Al surface at room temperature has been observed by electron energy loss *** CO dissociation rate is proportional to the oxygen contamination on the surface.

关键词： spectroscopy. surface. dissociation

dissociation, Dissociative Disorders and Partial Psychosis

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Open Journal of Medical Psychology 2022年第4期11卷 243-253页

作者： Domina Petric University Hospital Center Split Croatia

Background: dissociation may be defined as a psychopathological process in which an individual’s psyche splits into two or more parts. The division of personality is a key element in trauma, especially if the patient is not able to cope with it. At least one part of personality may be relatively able to understand and function in the objective reality, whilst other part(s) of the psyche may be more or less disorganized, dysfunctional and less able to understand the truth. Methods: literature review;conceptualization of dissociation, dissociative disorders and partial psychosis from medical and philosophical perspective. Conclusion: The core of dissociation and dissociative disorders is usually psychological trauma, especially emotional trauma, although some individuals may experience dissociation without any obvious cause or trigger. Carefully designed trauma-focused psychotherapy and psychosocial support are considered and must be further studied as the cornerstone of multidisciplinary approach in the treatment of dissociative disorders. Dissociative identity disorder in its severe form may resemble characteristics of partial psychosis. Some patients suffering from partial psychosis have narcissistic personality traits, such as shamelessness, magical thinking, arrogance, envy, entitlement, exploitation and bad boundaries, and therefore, developing healthy self-love, which is based on healthy self-criticism, realistic thinking, humility, gratefulness, democratic behavior, altruism and good boundaries, might be helpful for these patients.

关键词： dissociation Dissociative Disorders Partial Psychosis Psychological Trauma

dissociation of methanol in intense femtosecond laser field

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Chinese Science Bulletin 2002年第23期47卷 1973-1978页

作者： Xiaoping Tang Lirong Gao Yonglin Wang Cao Wang Sufan Wang Fan’ao Kong Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

Methanol was irradiated by 80 fs laser pulse, intensity range of 1013-1014 W/cm2. A TOF-mass spectrometer was coupled to the laser system and used to detect the ions produced. The parent ions CH3OH+ appeared firstly at the laser intensity of 1.4 ×1013 W/cm2. While the laser intensity was gradually increased, the parent ions were dissociated and the primary ions CH2OH+ were given as verified from the irradiation of deuterated methanol (CH3OD) showing the C-H bond cracking firstly. While the laser intensity was further increased to 2.0 ×1013 W/cm2, the C-O bonds of the parent ions also broke to give CH3+. When the laser intensity was higher, smaller fragment ions like CH+, C+, OH+ and O+ also appeared. Among the fragment ions, only H+ ion yield had anisotropic angular distribution dependence on the laser polarization vector in the dissociation of methanol. All the experimental observations show that the dissociation of methanol proceeds through stepwise mechanism but not Coulomb explosion.

关键词： intense laser field femtosecond laser dissociation methanol TOF-mass spectra.

Activated dissociation of H_(2) on the Cu(001)surface:The role of quantum tunneling

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Chinese Physics B 2023年第10期32卷 151-162页

作者：于小凡童洋武杨勇 Key Laboratory of Photovoltaic and Energy Conservation Materials Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230026China

The activation and dissociation of hydrogen molecules(H_(2))on the Cu(001)surface are studied *** first-principles calculations,the activation barrier for the dissociation of H_(2) on Cu(001)is determined to be~0.59 eV in *** is found that the electron transfer from the copper substrate to H_(2) plays a key role in the activation and breaking of the H–H bond,and the formation of the Cu–H *** stationary states are identified at around the critical height of bond breaking,corresponding to the molecular and the dissociative states,*** the transfer matrix method,we also investigate the role of quantum tunneling in the dissociation process along the minimum energy pathway(MEP),which is found to be significant at or below room *** a given temperature,the tunneling contributions due to the translational and the vibrational motions of H_(2) are quantified for the dissociation *** a wide range of temperature,the effects of quantum tunneling on the effective barriers of dissociation and the rate constants are *** deduced energetic parameters associated with the thermal equilibrium and non-equilibrium(molecular beam)conditions are comparable to experimental *** the low-temperature region,the crossover from classical to quantum regime is identified.

关键词： H_(2) Cu(001) dissociation quantum tunneling density functional theory(DFT) transfer matrix method