Immunoglobulin G

This music is based on a sequence determined by A. B. Edmundson and others for an Immunoglobulin G. The protein is a mutant form of IGG (IGG1 MCG) with a hinge deletion.

IGG consists of four chains: two heavy and two light. The heavy chains are about twice the length of the light chains. The four chains are all linked together by disulfide bonds between cysteine residues. Each light chain is linked to a heavy chain, and the two heavy chains are then linked together. The molecule is "left-justified" with the light and heavy chains running in parallel for the first half of the molecule, and the paired heavy chains running along together in the remaining half.

Immunoglobulins are composite molecules consisting of a variable and constant region. The variable regions compose about the first half of the light and the first quarter of the heavy chains.

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Immunoglobulin IGG1 (MCG) [ ] = beta-strands { } = turns

Light chain sequence PSA [LTQ] [PPSASG]{SLGQ} [SVTISCTG] {TSSD}{VGG} Y [NYVSWYQQ] {HAGK} [APKVII] {YEV} [NKR] PSGVPDR [FSGSK] {SGNT} [ASLTVS] GL{QAED} [EADYYCSSYE] {G SDN} [FVFGTGTKVTVLG] QPKAN [PTVTLFPP] {SSE} {ELQA} N [KATEVCLIS]{DYB} PGA [VTVAWKADG] SPVK [AGVETTK] PK {QSNN} KY [AASSYLSL] T {PEQW} KSH [RSYSCQVT] {HE GS} [TVEKT] VAPTECS

Heavy chain sequence PLV [LQESG] [PGLVK] PSEALSLTCTVSGDS {INTILY} [YWSWIRQ] {PPGK} [GLEWIGYIYYS] [GSTYG ]{NPSL}[KSRVTISVNT] { SK N} [QFYSKLS] SV {TAAD} [TAVYYCARVP] L [VVNPWGQGTLVTVSS] ASTKG [PSVFPLA] PSSKSTSGG [TAALGCLVKDY] FPQP [VTVS] {WNSG}ALT [SGVHTFPAVL] {QSSG} [LYSLSSVVTV] {PSSS} LGT [QTYICNVNHK] PS [NTKVDKR] VAPELLGG [PSVFLFP] P{KPKD} HTL {MISR} [TPEVTCVVVD] VSHEDPQ [VKFNWYVD] G [VQVH] NAK [TKPREQQ] {YNST} [YRVVSVLTVL] H {QN} WLDG [KEYKCKVS] {NKAL} PA [PIEKTIS] KAKGQ [PREPQVYTLPP] {SREE} M [TKNQVSLTCLVKGFYP] SD [IAVEWESN] [GQPE] N [NYKTTPPVL] {DSDG} [SFFLYSKLTV] {DKSR} {WQQG} N [VFSCSVMH] EA {LHNH} [YTQKSLS] L

Link to the Music: Immunoglobulin G

Notes on the music.

This piece is very simply set to facilitate comparison of the light and heavy chains, which play together throughout the piece. The harmoniousness of these two voices may arise from their having been derived from common ancestral molecules.

The music begins with a fast rhythmic section (on kalimba) taken from the IGG light chain sequence. Then both the heavy and light chain sequences come in, the light chain as a flute and the heavy chain as a singing voice. They continue until the end of the light chain, and both fade to leave the beginning rhythmic section playing alone.

The heavy and light chain voices return, this time enhanced with various percussive sounds representing the heavy and light chain beta strands (glockenspiel and a pingy orchestral sound) and the turns (marimba and tubular bells). Tympani strokes mark the cysteines of the heavy chains.

The light chain voices fade as the chain ends, leaving only the heavy chain sequence, with beta strands and turns, playing along with the rhythmic track.

Finally the heavy chain voices end as their sequence ends and leave the rhythm section accompanied by some fast chimes playing the sequence of the heavy chain again.