Institute for Biological Interfaces 2 (IBG-2)

www.kit.edu KIT – University of the State of Baden-Wuerttemberg and

National Research Center of the Helmholtz Association

Forschungsprojekte am LS Biochemie

Prof. Anne S. Ulrich (IOC & IBG-2)

www.kit.edu

antimicrobial

action

stress

response

cellular

delivery

virus

fusion

ion

channels

signal

transduction

protein

translocation

Transport

across

membranes

Anne S. Ulrich

- +

- +

- +

+ - + -

+ - - +

+ - - +

-H H-

N C

N C

- +

- +

- +

+ - + -

-H -H

-H -H

-H -H

-H -H

-H -H

New concepts for helix-helix recognition and assembly: charge zippers & H-bonds

-H -H

-H -H

Structure function applications

Anne S. Ulrich

- +

- +

- +

+ - + -

+ - - +

+ - - +

-H H-

N C

N C

- +

- +

- +

+ - + -

-H -H

-H -H

-H -H

-H -H

-H -H

TisB: bacterial

stress response

induces biofilms

New concepts for helix-helix recognition and assembly: charge zippers & H-bonds

TatA: oligomeric

pore for protein

translocation

Dermcidin:

antimicrobial peptide

from human sweat

BsrG:

mysterious

bacterial toxin

PDGF-receptor:

activated by viral

E5 oncoprotein

-H -H

-H -H

Structure function applications

Anne S. Ulrich

Materials: Synthetic peptides (19F-NMR labels): Parvesh Wadhwani

Recombinant proteins (15N-NMR): Dirk Windisch, Torsten Walther

Liposome technology, amino acids: Sergii Afonin

Methods: Solid-state NMR: Stephan Grage, Erik Strandberg

Circular dichroism: Jochen Bürck

Fluorescence, FRET: Johannes Reichert

Microbiology assays: Marina Berditsch

Experimental approach

N

O

H

H

CF3

Smol

Oriented CD ssNMR

Anne S. Ulrich

Helices in membranes

Tat translocase:

flip of short TM-helix

PDGF-receptor:

clustering via long E5

amphiphilic helices

& charge zippers

Anne S. Ulrich

Example: amphiphilic „molecular rulers“

+ + + + + + + +

repeat sequence: KIAGKIA - KI(15N-Ala)GKIA - KIAGKIA - KIAGKIA

21 Å

42

Å

Anne S. Ulrich

KIA14

KIA15

KIA17

KIA19

KIA21

KIA22

KIA24

KIA26

KIA28

31P-NMR

aligned lipid (DMPC)

misaligned

lipid

15N-NMR

inserted peptide surface-bound

disordered

peptide

Anne S. Ulrich

Helix length ↔ membrane thickness

too short well matched too long

no effect stable pore

Deduce thickness in living cells by antimicrobial/hemolysis assays:

E. coli < S. aureus ≈ P. aeruginosa < E. faecalis ≈ red blood cell

24 Å 30 Å 30 Å 34 Å 34 Å

Calibrate thresholds for vesicle leakage with different bilayer thicknesses.

disruption

Anne S. Ulrich