His design allowed air inside the flasks to be exchanged with air from the outside, but prevented the introduction of any airborne microorganisms, which would get caught in the twists and bends of the flasks’ necks.

#Id: 7687

#Unit 1. Molecules and their Interaction Relevant to Biology

                                                               Helix-turn-Helix

#Id: 7688

#Unit 1. Molecules and their Interaction Relevant to Biology

                                                       Zinc Finger Motif

Zinc atom stabilizes the structure/fold by coordination bonds

Each motif contains about 30-50 amino acids

Contains regular patterns of Cys / His, which coordinate with Zinc atom

Contains one helix and two small anti-parallel beta sheets in each finger

Zinc holds helix and beta-sheets together

Helix binds to DNA

#Id: 7689

#Unit 1. Molecules and their Interaction Relevant to Biology

                                         Zinc Finger Motif

 


#Id: 7690

#Unit 1. Molecules and their Interaction Relevant to Biology

                                                                  bab Motif

Two beta strands are connected by a long region containing a helix

These beta strands form parallel beta-sheets

The loop regions connecting sheet and helix can have different length

The helix axis is generally parallel to beta-sheets

Three secondary structures are stabilized by hydrophobic interactions


#Id: 7691

#Unit 1. Molecules and their Interaction Relevant to Biology

                                             bab Motif

These motifs are generally found in right handed helix above the plane of the beta sheet

Almost all the proteins containing parallel beta sheets have this motif. 

The helix is generally not seen below the plane of beta sheets                                           

#Id: 7692

#Unit 1. Molecules and their Interaction Relevant to Biology

                                                  bab Motif