The NMR structure of human obestatin in membrane-like environments: insights into the structure-bioactivity relationship of obestatin.
The quest for therapeutic applications of obestatin involves, as a first step, the determination of its 3D solution structure and the relationship between this structure and the biological activity of obestatin. On this basis, we have employed a combination of circular dichroism (CD), nuclear magnetic resonance (NMR) spectroscopy, and modeling techniques to determine the solution structure of human obestatin (1). Other analogues, including human non-amidated obestatin (2) and the fragment peptides (6-23)-obestatin (3), (11-23)-obestatin (4), and (16-23)-obestatin (5) have also been scrutinized. These studies have been performed in a micellar environment to mimic the cell membrane (sodium dodecyl sulfate, SDS). Furthermore, structural-activity relationship studies have been performed by assessing the in vitro proliferative capabilities of these peptides in the human retinal pigmented epithelial cell line ARPE-19 (ERK1/2 and Akt phosphorylation, Ki67 expression, and cellular proliferation). Our findings emphasize the importance of both the primary structure (composition and size) and particular segments of the obestatin molecule that posses significant α-helical characteristics. Additionally, details of a species-specific role for obestatin have also been hypothesized by comparing human and mouse obestatins (1 and 6, respectively) at both the structural and bioactivity levels.
Área de Endocrinología Molecular y Celular, Instituto de Investigación Sanitaria (IDIS), Complejo Hospitalario Universitario de Santiago de Compostela (CHUS), SERGAS, Santiago de Compostela, Spain.
Begoña O
BO
Alén
Lidia
L
Nieto
Uxía
U
Gurriarán-Rodríguez
Carlos S
CS
Mosteiro
Juan C
JC
Álvarez-Pérez
María
M
Otero-Alén
Jesús P
JP
Camiña
Rosalía
R
Gallego
Tomás
T
García-Caballero
Manuel
M
Martín-Pastor
Felipe F
FF
Casanueva
Jesús
J
Jiménez-Barbero
Yolanda
Y
Pazos
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry*; D049109:Cell Proliferation / Q000187:drug effects; D002942:Circular Dichroism / Q000379:methods; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D054439:Ghrelin / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D051379:Mice; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology; D017386:Sequence Homology, Amino Acid; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013329:Structure-Activity Relationship
C495797:GPR39 protein, human; D054439:Ghrelin; D019394:Ki-67 Antigen; D008823:Micelles; D043562:Receptors, G-Protein-Coupled; D012996:Solutions; D012967:Sodium Dodecyl Sulfate