A stable version MERA software package can be downloaded below. When downloading software from this website, you are agreeing to our Terms of Use, including the terms that there is no right to privacy on this system, and that the software from this website is not to be redistributed without permission from the authors. The MERA package provides the hardware & OS versions of linux9, and mac (see here for a definition of those hardware & OS versions by the NMRPipe system), and requires multiple Unix programs and other external software packages in order to use all its features and/or to perform it in an efficient way (see details below).

The most common MERA installation procedure on an Unix environment (linux9 and mac) will involve:

Create a directory for the MERA installation [for example, type mkdir /disk1/MERA in an "xterm" terminal window]. Go to the selected install directory [cd /disk1/MERA]. Download and store the MERA installation files (mera.tZ, install.com) into the selected install directory Via a web browser: Right-click the download links below and select "Save Target As", "Save Link As" or "Download Linked File (As)" (depending on the browser type), and save the files into the selected install directory (Be sure to retain the exact file name shown below). Or via the unix command "wget": wget http://spin.niddk.nih.gov/bax/software/MERA/mera.tZ wget http://spin.niddk.nih.gov/bax/software/MERA/install.com Execute the install.com script: In most cases, no arguments will be required. It will be sufficient to make the install scripts executable (by typing "chmod +x install.com"), then run the install.com script. Use the command ./install.com +help to generate a list of install command-line options.

There is also a Web-Based version of MERA which can be used directly without installing MERA. You can access this Web-based system, along with other facilities for manipulating chemical shifts, dipolar couplings, and molecular structures at the Bax Group NMR Server site:

MERA Installation Files	MERA Web Server	Coil Library (Raw)
(Version 1.00 Rev 2015.198.12.12) install.com [size: 6KB] mera.tZ [size: 25MB]		coil_library_2015.tar.Z [size: 4MB]

As input data, the MERA program currently utilizes up to six types of J couplings ( ³J_HNHα, ³J_C'C', ³J_C'Hα, ¹J_HαCα, ²J_CαN and ¹J_CαN), for which the Karplus parameters used are listed below:

³J_HNHα = 8.83*cos²(φ-60)-1.29*cos(φ-60)+0.20

³J_C'C' = 1.78*cos²(φ)-0.95*cos(φ)+0.46

³J_C'Hα = 3.78*cos²(φ-60)+1.92*cos(φ-60)+1.19

¹J_HαCα = A+1.4*sin(ψ+138)-4.1*cos(2*(ψ+138))+1.7*cos(2*(φ+30))
   where
   A = 143.9 for Ala
   A = 142.8 for Arg
   A = 144.5 for Asn
   A = 144.4 for Asp
   A = 143.5 for Cys
   A = 142.9 for Gln
   A = 142.8 for Glu
   A = 143.9 for His
   A = 141.7 for Ile
   A = 142.5 for Leu
   A = 142.8 for Lys
   A = 142.8 for Met
   A = 144.0 for Phe
   A = 150.1 for Pro
   A = 143.5 for Ser
   A = 142.4 for Thr
   A = 144.1 for Trp
   A = 144.1 for Tyr
   A = 141.7 for Val


²J_CαN = -1.51*cos(ψ)-0.66*cos²(ψ)+C
   where
   C = 8.15 for Ala/Arg/Cys/Gln/Glu/His/Lys/Met/Pro/Trp
   C = 8.35 for Asn/Asp
   C = 7.55 for Ile
   C = 8.05 for Leu/Phe/Tyr
   C = 7.65 for Ser
   C = 7.75 for Thr
   C = 7.65 for Val


¹J_CαN = 1.7*cos²(ψ)-0.98*cos(ψ)+9.51+offset
   where
   offset = 0.2 for Asn
   offset = 0.1 for Asp
   offset =-0.1 for Leu
   offset = 0.1 for Phe/Tyr
   offset = 0.6 for Ser/Thr
   offset = 0.1 for Val