Hippo

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A peptide folds and inserts into a membrane; the membrane is represented by an implicit Generalized Born model.

Hippo is a software package for simulation and analysis of bio-molecules at an atomic level. It has been specifically developed for very efficient protein folding studies in aqueous and membrane environments. The code is very fast due to optimized and hand-coded assembly routines which make use of fast multi-media instructions on modern x86 cpus. Hippo is (partially) parallelized (using industry-standard OpenMP).


Contents

Features

Not this hippo.

Simulation methods

Force fields

  • OPLS-AA [5, 6]

Solvation models

  • explicit solvent (water: TIP4P [7], SPC [8])
  • Generalized Born implicit solvent (GB/SA)
  • Generalized Born implicit membrane (GB/IM) [1, 4, 9, 10]

Enhanced productivity

A number of features make it easy to use Hippo so that one can spend more time on working on problems and less time on setting up structures or dealing with system crashes:

  • seamless restarts
  • intelligent pdb structure loader: reads most pdbs, can complete missing atoms, and builds the topology
  • graphical frontend under development (Windows only)

Analysis

Adiabatic Generalized Born energy surface for different positions and orientations of a helical peptide in a membrane (output from the translation+rotation energy scan analysis tool).

A growing number of analysis tools are built into Hippo, for instance

adiabatic translation+rotation energy scan
determines the Generalized Born energy of a peptide in a membrane [11, 12]; this allows to decide if a (typically helical) peptide inserts into the membrane and at which depth and angle or if it prefers a surface-bound or even a fully solvated state
RMSD
calculates the root mean square deviation of trajectory frames to a reference structure
helicity
degree of helicity of segments along trajectory
Z - tilt - kink graph
Calculates center of mass, tilt angle, and kink angle of a peptide in a membrane as a function of simulation time. The membrane is in the xy plane, with z = 0 the membrane center. Kink angle is with respect to the membrane normal. [13]
cluster
Performs a cluster analysis using the pairwise method by Daura et al.[14]
fit to phase
recenters trajectory on the centre of mass of a phase (such as a lipid membrane)
fit solute to previous frames
Generate a PDB movie by RMSD fitting the solute of each frame to the previous frame.

The Hippo output format is a binary xyz-movie (see the definition of the xyz format); thus many other analysis tools can also be used.

Installation

Download

Binaries are publicly available from the Biowerkzeg.com download page for Linux and Windows.

Installing the software

Unzip the downloaded file. It will unpack into its own hippo directory where you will find

  • compiled executables (see below)
  • the manual (pdf)
  • the license (to which you consent by downloading)
  • the OPLS-AA forcefield file (in Hippo format)
  • the readme.txt file
  • the testjobs directory with example systems
Hippo executables
cpu Linux Windows
SSSE3 (Core Duo,...) hippo hippo.exe
SSE (PIII,P4,Athlon,...) hippo_p3 hippo_p3.exe

The package includes binaries that run under Linux and Windows on any Intel or AMD processor that has the SSE or SSSE3 multi media instructions. Depending on your system and needs, choose an executable from the package as shown in the table Hippo executables.

If in doubt, simply try them out in order; if it will not run you will receive an error message such as

Fatal Error: This program was not built to run on the processor in your system.
The allowed processors are: Intel(R) Core(TM) Duo processors and compatible Intel processors 
with supplemental Streaming SIMD Extensions 3 (SSSE3) instruction support.

In this case try the hippo_p3 or hippo_p3.exe executable. If this still doesn't work, post a request in the Hippo Installation forum.

Executables with the _mpi extension have been compiled with MPI support (mpich2) and are only used for replica exchange simulations (REXMD). If you just want to run multithreaded simulations just use the standard binaries (which are all compiled with OpenMP).

Test cases

The testjobs directory contains a number of testcases.

Run the calc_testjobs_linux.bat or calc_testjobs_win32.bat script in order to perform all tests. On modern processors this should take between 2 and 4 Minutes.

Use the tests in order to get started in running your own systems.


References

Error fetching PMID 18428040:
Error fetching PMID 17600830:
Error fetching PMID 17218457:
Error fetching PMID 16339877:
Error fetching PMID 16913813:
Error fetching PMID 15723347:
Error fetching PMID 14871118:
Error fetching PMID 12417206:
  1. Jakob P. Ulmschneider and Martin B. Ulmschneider. Sampling efficiency in explicit and implicit membrane environments studied by peptide folding simulations. Proteins 10.1002/prot.22270.

    [Proteins2008]

  2. Error fetching PMID 14871118: [JACS2004]
  3. Error fetching PMID 16913813: [JPhysChemB2006]
  4. Error fetching PMID 17600830: [Proteins2007]
  5. W. L. Jorgensen, D. S. Maxwell, and J. Tirado-Rives. Development and testing of the OPLS all-atom force field on conformational energetics and properties of organic liquids. J. Am. Chem. Soc., 118(45):11225–11236, 1996. 10.1021/ja9621760.

    [Jorgensen1996]

  6. George A. Kaminski, Richard A. Friesner, Julian Tirado-Rives, and William L. Jorgensen. Evaluation and reparametrization of the OPLS-AA force field for proteins via comparison with accurate quantum chemical calculations on peptides. J. Phys. Chem. B, 105(28):6474–6487, 2001. 10.1021/jp003919d.

    [Kaminski2001]

  7. W. L. Jorgensen and J. D. Madura. Temperature and size dependence for Monte-Carlo simulations of TIP4P water. Mol. Phys., 56(6):1381–1392, December 1985.

    [Jorgensen1985]

  8. H. J. C. Berendsen, J. P. M. Postma, W. F. van Gunsteren, and J. Hermans. Interaction models for water in relation to protein hydration. In B. Pullman, editor, Intermolecular Forces, page 331. D. Reidel Publishing Company, Dordrecht, Holland, 1981.

    [Berendsen1981]

  9. Error fetching PMID 17218457: [BJ2007]
  10. Error fetching PMID 15723347: [Proteins2005]
  11. Error fetching PMID 18428040: [MMB2008]
  12. Error fetching PMID 16339877: [BJ2006]
  13. Error fetching PMID 12417206: [Cordes2002]
  14. X Daura, K Gademann, B Jaun, D Seebach, WF van Gunsteren, and AE Mark. Peptide folding: When simulation meets experiment. Angewandte Chemie-International Edition, 38 (1-2):236–240, 1999. 10.1002/(SICI)1521-3773(19990115)38:1/2<236::AID-ANIE236>3.0.CO;2-M.

    [Daura1999]

All Medline abstracts: PubMed HubMed
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