Computer simulations of the dynamics of human choriogonadotropin and its ? subunit

Kouwijzer, Milou; Berendsen, Herman J. C.; Grootenhuis, Peter D. J.

doi:10.1002/(sici)1097-0134(19991201)37:4<668::aid-prot16>3.0.co;2-3

Cited by 3 publications

(2 citation statements)

References 34 publications

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“…Lu and Schulten (2000) have shown that the energy barrier preventing one domain of the titin immunoglobulin (a β-stranded muscle protein) from stretching is overcome with the assistance of water molecules, which weaken several inter-strand H-bonds. A total of 75 ns trajectories at 400 K on human choriogonodotropin (a hormone involved in reproduction) revealed interesting structural features (Kouwijzer et al 1999).…”

Section: Simulations Of Biomedical Importancementioning

confidence: 99%

“…Analysis of 2 ns of MD of the enzyme with two Mg 2+ placed in regions based on alignment with ASV integrase, have shown that there is a high degree of flexibility in an important region of the enzyme (Lins et al 2000). The fluctuations of the chains of apohuman glutathione transferase P1-1 enzyme (Stella et al 1999), human choriogonadotropin (Kouwijzer et al 1999) and neurophysins (Kazmierkiewicz et al 1999). Balsera et al (1995) have used PCA for their 500 ps simulation on G-actin.…”

Section: Analysis Of Dynamicsmentioning

confidence: 99%

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Simulated dynamics and biological macromolecules

2003

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We present a review of the use of molecular dynamics techniques to study the behaviour of proteins. The application of such methods to biological macromolecules has evolved directly from its use to study simpler physical and chemical systems. We describe the methods typically used in producing multiple nanosecond atomic trajectories. This technique is now so common that it is impossible to review the whole area. Therefore, we have focused on three areas, namely the application to proteins of biomedical importance, to folding of proteins from a random conformation to a stable well-defined tertiary structure and to the reverse process, that of unfolding. Finally, we describe some methods which have been developed to analyse complex trajectories with the aim of defining the most important features of protein dynamics and changes in conformation.

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Section: Simulations Of Biomedical Importancementioning

confidence: 99%

Section: Analysis Of Dynamicsmentioning

confidence: 99%

Simulated dynamics and biological macromolecules

2003

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A Prototype Manipulator for Magnetic Resonance-Guided Interventions Inside Standard Cylindrical Magnetic Resonance Imaging Scanners

Tsekos

Özcan

Christoforou

2005

Journal of Biomechanical Engineering

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The aim of this work is to develop a remotely controlled manipulator to perform minimally invasive diagnostic and therapeutic interventions in the abdominal and thoracic cavities, with real-time magnetic resonance imaging (MRI) guidance inside clinical cylindrical MR scanners. The manipulator is composed of a three degree of freedom Cartesian motion system, which resides outside the gantry of the scanner, and serves as the holder and global positioner of a three degree of freedom arm which extends inside the gantry of the scanner At its distal end, the arm's end-effector can carry an interventional tool such as a biopsy needle, which can be advanced to a desired depth by means of a seventh degree of freedom. These seven degrees of freedom, provided by the entire assembly, offer extended manipulability to the device and a wide envelope of operation to the user, who can select a trajectory suitable for the procedure. The device is constructed of nonmagnetic and nonconductive fiberglass, and carbon fiber composite materials, to minimize artifacts and distortion on the MR images as well as eliminate effects on its operation from the high magnetic field and the fast switching magnetic field gradients used in MR imaging. A user interface was developed for man-in-the-loop control of the device using real-time MR images. The user interface fuses all sensor signals (MR and manipulator information) in a visualization, planning, and control command environment. Path planning is performed with graphical tools for setting the trajectory of insertion of the interventional tool using multislice and/or three dimensional MR images which are refreshed in real time. The device control is performed with an embedded computer which runs real-time control software. The manipulator compatibility with the MR environment and image-guided operation was tested on a 1.5 T MR scanner.

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Rapid Maturation of Glycoprotein Hormone Free α-Subunit (GPHα) and GPHαα Homodimers

Krause

Berger

Roig

et al. 2007

Molecular Endocrinology

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The dynamics of glycoprotein hormone alpha-subunit (GPHalpha) maturation and GPHalpha alpha homodimer formation were studied in presence (JEG-3 choriocarcinoma cells) and absence (HeLa cells) of hCGbeta. In both cases, the major initially occurring GPHalpha variant in [35S]Met/Cys-labeled cells carried two N-glycans (M(r app) = 22 kDa). Moreover, a mono-N-glycosylated in vivo association-incompetent GPHalpha variant (M(r app) = 18 kDa) was observed. In JEG-3 cells the early 22-kDa GPHalpha either associated with hCGbeta, or showed self-association to yield GPHalpha alpha homodimers, or was later converted into heavily glycosylated large free GPHalpha (M(r app) = 24 kDa). Micro-preparative isolation of intracellular GPHalpha alpha homodimers of JEG-3 cells and their conversion by reduction revealed that they consisted of 22-kDa GPHalpha monomers and not of large free GPHalpha. In HeLa cells, the large free GPHalpha variant was not observed, whereas GPHalpha alpha homodimers were present. Intracellularly, early GPHalpha alpha homodimers (35 kDa) and late variants (JEG-3: 44 kDa, HeLa: 39 kDa) were found. Both cell types secreted 45 kDa GPHalpha alpha homodimers. Large free GPHalpha and GPHalpha alpha homodimers were more rapidly sialylated than hCG alphabeta-heterodimers indicating a sequestration mechanism in the secretory pathway. In GPHalpha alpha homo- as well as hCG alphabeta-heterodimers the subunit interaction site, located on loop 2 of GPHalpha (amino acids 33-42), became immunologically inaccessible indicating similar spatial orientation of GPHalpha in both types of dimers. The studies demonstrate the formation, in vivo dynamics of GPHalpha alpha homodimers, and the pathways of the cellular metabolism of variants of GPHalpha, monoglycosylated GPHalpha and large free GPHalpha.

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Computer simulations of the dynamics of human choriogonadotropin and its ? subunit

Cited by 3 publications

References 34 publications

Simulated dynamics and biological macromolecules

Simulated dynamics and biological macromolecules

A Prototype Manipulator for Magnetic Resonance-Guided Interventions Inside Standard Cylindrical Magnetic Resonance Imaging Scanners

Rapid Maturation of Glycoprotein Hormone Free α-Subunit (GPHα) and GPHαα Homodimers

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