The CD Spectra Analyser Plus system provides a simple way to analyse single or multiple CD spectra, resulting in data that can be applied in a quantitative form. The program is composed of a module called Convex Constraint Algorithm (CCA) for the simultaneous analysis of multiple spectra. The analyser system incorporates also a routine for analysing single CD spectra (called LINCOMB) as well as various spectral data set generators. The CCA algorithm was originally developed by Prof. G. Tusnády (Mathematical Research Inst. of the Hungarian Academy of Sciences, Budapest) and by Prof. A. Perczel (L. Eötvös University Budapest, Hungary), and coded for PC using the Borland Turbo Basic system by A. Perczel and G.Tusnády in the period of 1988-1989. Two original publications are reporting the method:

• A. Perczel, M. Hollosi, G. Tusnady, and G. D. Fasman "Convex Constraint Decomposition of Circular Dichroism Curves of Proteins." Croatica Chim. Acta. (1989), 62, 189-200
• A. Perczel, M. Hollosi, G. Tusnady and G. D. Fasman "Convex constraint analysis: a natural deconvolution of circular dichroism curves of proteins." Protein Engineering (1991), 4, 669-679

Since 1990, the CCA and the LINCOMB programs are continuously applied in several laboratories all over the world. For selected publications see the list below:

• A. Perczel, M. Hollosi, Bruce M. Foxman and G. D. Fasman "Conformational Analysis of Pseudocyclic Hexapeptides Based on Quantitative Circular Dichroism (CD), NOE and X-ray Data. The Pure CD Spectra of type I and type II b-Turn." J.Am.Chem.Soc. (1991), 113, 9772-9784
• A. Perczel, K. Park and G. D. Fasman "Deconvolution of the Circular Dichroism Spectra of proteins: The Circular Dichroism Spectra of the Antiparallel b-Sheet in proteins." Proteins Struct. Funct. and Genet. (1992), 13, 57-69
• A. Perczel and G. D. Fasman "Quantitative Analysis of Cyclic b-Turn Models." Protein Science (1992), 1, 378-395
• K. Park, A. Perczel and G. D. Fasman "Differentiation between transmembrane helices and peripheral helices by the deconvolution of circular dichroism spectra of membrane proteins." Protein Science (1992), 1, 1032-1049
• M. Hollosi, L. Urge, A. Perczel, J. Kajtar, I. Teplan, L. Otvos,Jr., and G. D. Fasman "Metal Ion-induced Conformational Changes of Phosphorylated Fragments of Human Neurofilamnet (NF-M) Protein." J. Mol. Biol. (1992), 223, 673-682
• A. Perczel, K. Park, and G. D. Fasman "Analysis of the Circular Dichroism Spectra of Proteins Using the Convex Constraint Algorithm: a Practical Guide." Anal. Biochem. (1992), 203, 83-93
• A. Perczel "From qualitative to quantitative analzses of Circular Dichroism spectra using the Convex Constraint Algorithm." in Recent Experimental and Computational Advances in Molecular Spectroscopy. [Fausto,R. (Ed)] Kluwer Acad. Publisher (Netherlands) 1993, 63-77
• A. Perczel, E. Lang, M. Hollosi and G. D. Fasman "Synthesis and conformational analyseis of N-glycopeptides. II. CD, Molecular Dynamics and NMR spectroscopic studies on linear N-glycopeptides." Biopolymers (1993),33, 665-685
• A. Perczel and G. D. Fasman "Does the extension of the CD spectral range improves protein secondary structure analyses?" Anal. Biochem. (1993), 48, 19-29

In 1993, the original program was coded using the C language and sheltered by a common driver system to make the system user-friendly (Ver. # 1.0). This work was done by I. Jákli (L. Eötvös University Budapest, Hungary) and supervised by Prof. A. Perczel.

This version (32bit 0.2b1) of the program was rewritten for 32 bit Windows by I. Jákli, jimre@para.chem.elte.hu (L. Eötvös University Budapest, Hungary). This version incorporates a somewhat modified simplex routine developed by G. Tusnády (Mathematical Research Inst. of the Hungarian Academy of Sciences, Budapest) in 1995.

For scientific consultation please do not hesitate to contact Prof A. Perczel (Department of Chemistry, L. Eötvös University Budapest, H-1518 Budapest, P.O.B.32, Hungary, tel: 36-1-209-0555, fax: 36-1-209-0602, e-mail: "perczel@chem.elte.hu").

If you have received the program and installed it successfully please send us a postcard of your city or university so that you get updated of the latest version of the program (A. Perczel, Department of Chemistry, Loránd Eötvös University Budapest, H-1518 Budapest, P.O.B.32, Hungary).