G PROTEINS alpha subunits
Hulya Cabadak
Paula Garcia Nogales
Barbara Guinea
Types of Gα subunits
1
Aim of the project : To study the structure of G α subunits by
comparing a member of each family.
G proteins in the Genome
Gαs
Gαi
Chromosome 20 q13.2
Chromosome 7 q21
2
G 12
N-terminal
G_s_
(βγ binding region) G_i_
G_q_
1
1
1
1
--------MACCLSEEA----------------KEARRINDEIERQLRRDKRDARRELKL
MSGVVRTLSRCLLPAEAGGARERRAGSGARDAEREARRRSRDIDALLARERRAVRRLVKI
-MGCLGNSKTEDQRNEE----------------KAQREANKKIEKQLQKDKQVYRATHRL
-MGCT-------LSAED----------------KAAVERSKMIDRNLREDGEKAAREVKL
G_q_
G 12
G_s_
G_i_
37
61
44
37
LLLGTGESGKSTFIKQMRIIHGSGYSDEDKRGFTKLVYQNI---------------FTAM
LLLGAGESGKSTFLKQMRIIHGREFDQKALLEFRDTIFDNI---------------LKGS
LLLGAGESGKSTIVKQMRILHVNGFNGEGGEEDPQAARSNSDGEKATKVQDIKNNLKEAI
LLLGAGESGKSTIVKQMKIIHEAGYSEEECKQYKAVVYSNT---------------IQSI
G_q_
G 12
G_s_
G_i_
82
106
104
82
QAMIRAMDTLKIPYKYE--HNKAHAQLVREVDVEKVSAFENP----YVDAIKSLWNDPGI
RVLVDARDKLGIPWQYS--ENEKHGMFLMAFENKAGLPVEPATFQLYVPALSALWRDSGI
ETIVAAMSNLVPPVELANPENQFRVDYILSVMNVPDFDFPPEF----YEHAKALWEDEGV
IAIIRAMGRLKIDFGDSARADDARQLFVLAGAAEEGF-MTAEL----AGVIKRLWKDSGV
G_q_
G 12
G_s_
G_i_
136
164
160
137
QECYDRRREYQLSDSTKYYLNDLDRVADPAYLPTQQDVLRVRVPTTGIIEYPFDLQSVIF
REAFSRRSEFQLGESVKYFLDNLDRIGQLNYFPSKQDILLARKATKGIVEHDFVIKKIPF
RACYERSNEYQLIDCAQYFLDKIDVIKQADYVPSDQDLLRCRVLTSGIFETKFQVDKVNF
QACFNRSREYQLNDSAAYYLNDLDRIAQPNYIPTQQDVLRTRVKTTGIVETHFTFKDLHF
G_q_
G 12
G_s_
G_i_
196
224
220
197
DXXG
RMVDVGGQRSERRKWIHCFENVTSIMFLVALSEYDQVLVESDNENRMEESKALFRTIITY
KMVDVGGQRSQRQKWFQCFDGITSILFMVSSSEYDQVLMEDRRTNRLVESMNIFETIVNN
HMFDVGGQRDERRKWIQCFNDVTAIIFVVASSSYNMVIREDNQTNRLQEALNLFKSIWNN
KMFDVGGQRSERKKWIHCFEGVTAIIFCVALSDYDLVLAEDEEMNRMHESMKLFDSICNN
G_q_
G 12
G_s_
G_i_
256
284
280
257
NKXD
PWFQNSSVILFLNKKDLLEEKIM--YSHLVDYFPEYDGPQRDAQAARE-----------KLFFNVSIILFLNKMDLLVEKVK--TVSIKKHFPDFRGDPHRLEDVQR-----------RWLRTISVILFLNKQDLLAEKVLAGKSKIEDYFPEFARYTTPEDATPEPGEDPRVTRAKY
KWFTDTSIILFLNKKDLFEEKIK--KSPLTICYPEYAGSNTYEEAAA-------------
G_q_
G 12
G_s_
G_i_
302
330
340
302
FILKMFVDLNPDSD---KIIYSHFTCATDTENIRFVFAAVKDTILQLNLKEYNLV
YLVQCFDRKRRNRS---KPLFHHFTTAIDTENVRFVFHAVKDTILQENLKDIMLQ
FIRDEFLRISTASGDGRHYCYPHFTCAVDTENIRRVFNDCRDIIQRMHLRQYELL
YIQCQFEDLNKRKD--TKEIYTHFTCATDTKNVQFVFDAVTDVIIKNNLKDCGLF
GXGXXGKS
GTP binding site
Receptor coupling site
C-terminal
Structure of a Gα subunit
Rd
(Ras like domain)
Hd (helical domain)
3
Rd
Hd
6 α-helices
α subunit
βγ subunit
4