COHPARISOH0F W - GL :ADIN c o;·PONENTS EI N-Ti~R1'1INALAMINO !\CIT. ..);:, QIJi::tICI:ll ;

Jean - Claude Autran,

Charles

C. Nimmo, i::1.len Lew, and Donald D. i\a::;arda

·..:estern Regional Hes earch Center, 3erkeley , California 94710, USA

U. S. Department

of Agricul turc,

SiA-r'R,

.

(,J-Gliadin proteins from bread ·,meat ( Tritic'.:..l:i aes Livrnn va riL:ty Justin), Triticum :-:0 noc Oc8um, and Ae gilops werecompared by ii-terminal amino acid sequenci ng . Corr.ponents extracted from seeds were purified by ge l- filtration and ion-exchange chroma tog raphy , i!.ach of two $l iadins from Justin (one co:1trolled by a gene on chromos ome lD and the othe r by a gene on chr omosome lB) gave mainly a single band upon ge l el ectroJXioresis in aluminum lactate buffer (pH J.2); th e c oQponent from T. monococcum also gave ~4inly a single ba.Jld upon electro 0horesis. These three components were s e quenced through 25-28 re s idues fr om the N- terminus prepared _fr om l\e. squarrosa gave of each of the uroteins . The fraction 7 two closely-spaced bands upon electro"!Xloresis. Only el10\.1i h of this fracti on ·,;as obtained for a s ing le experiment that wa s carried throu gh 14 cycles • .t..11 of the::,e ((.1-e;liadins differed from one another in se quence altho ugh some homolo gy was evident among them . Homol ogy could be frmroved by a realir.n mcn t of sequences based on the ass um~t i o~ that insertions judicious into or deletio'!1S fr om t he base sequenc e of an ancestral structural ge ne hav e occ urr ed durjn ~ th e course of evolution of the structura'J. r.:enes coding for these !"r otei ns . The com~onent fro m T . monococc um gave a double sequence with the minor se qu e nce bein g the s:1.me - as the major sequence excent for being di snlace d by one resid ue as a consequ en ce of th e abs e nce cf th e IJ-t er r:iincil ai'lino acid. This an'."'arcntly nure c omnon e nt was a.ct:1ally a mixtur e of t.,,o co r:::~onent s that. differed fro m one anot he r b•: a s Lnc1e :~videnc e for a r epe atin g sequence of f ive a:--ino U-terminal a rr.inc J.dd. -'lcids was fm.:.nd in tw o of the components.

squa~a

Exposeau Colloque FAO/AIEA"Amelioration des Proteinesdes Cereales et des Legumineuses", 4-8 septembre,Neuherberg,RFA.

,.

~

.

Rf alignment

"

efseruences to em_phas!Je Homolog-5

W-GLI (J-10) K~

P-Q-Q-P-Y-P-Q-Q-P-Y-PE- L-Q-S-P-Q-Q E-L-Q-S-P-Q-zG ~G-G-P-Y-P-G-G-P-Y L-Y W -G LI (T.M.) A-R-Q-L-N-P-S-D-Q

A = ALA, R= ARG, Q = GLN• L= LEU, N~ ASN, P= PRO, S= SER, D= ASP,

E= GLU, Y = TYR, F=

PHE,

K=

LYS,

G=

GL Y,

H= HIS, T = THR

.

I