CCL: CHARMM: total charge not an integer

 Sent to CCL by: "Venable, Richard (NIH/NHLBI) [E]"
 [venabler\a/nhlbi.nih.gov]
 The forums at www.charmm.org can be quite helpful, esp. via the Search feature.
 Molecules should have an integer charge; yours does not.  Since chain terminal
 patches NNUT and CNUT are not part of the standard distribution, you should
 either look more closely at these two patch residues, or use more standard pairs
 of end patches such as NTER/CTER (zwitterion) or ACE/CT3 (neutral, methyl).
 --
 Rick Venable     5635 FL/T906
 Membrane Biophysics Section
 NIH/NHLBI Lab. of Computational Biology
 Bethesda, MD  20892-9314   U.S.A.
 (301) 496-1905   venabler AT nhlbi*nih*gov
 On 8/13/09 5:43 PM, "Natalia Zakharova nlzakh,,wsu.edu"
 <owner-chemistry]~[ccl.net> wrote:
 Sent to CCL by: "Natalia  Zakharova" [nlzakh^_^wsu.edu]
 I am currently trying to perform CHARMM (version c32b2) calculation for a
 tri-peptide WGY (Trp-Gly-Tyr) with tryptophan side chain protonated at nitrogen.
 When attmepting to run CHARMM, I get the following error:
  ***** Message from SEQRDR ***** THE SYSTEM CONTAINS  1 TITRATABLE GROUPS
  THE USER MUST PREDETERMINE THE PROTONATION STATE THROUGH THE SEQUENCE AND RTF
  HIS -  0  ASP -  0  GLU -  0  LYS -  0  TYR -  1
  CHARMM>    GENErate wgyneutral FIRST NNUT LAST CNUT SETup
  THE PATCH 'NNUT' WILL BE USED FOR THE FIRST RESIDUE
  THE PATCH 'CNUT' WILL BE USED FOR THE LAST  RESIDUE
  GENPSF> Segment   1 has been generated. Its identifier is WGYNEUTR.
  Warning from PSFSUM: The sum of charges (    1.090000) is not an integer
       ***** LEVEL  0 WARNING FROM <PSFSUM> *****
       ***** Total charge not an integer
 I absolutely have no idea how to fix this issue and any help will be
 appreciated.
 Thank you,
 Natalia Zakharova