𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Head-to-head dimerization of parallel β helices in a synthetic model of the linear gramicidins

✍ Scribed by Gian Paolo Lorenzi; Christoph Gerber; Hans Jäckle

Publisher
Wiley (John Wiley & Sons)
Year
1984
Tongue
English
Weight
572 KB
Volume
23
Category
Article
ISSN
0006-3525

No coin nor oath required. For personal study only.

✦ Synopsis

In chloroform solution, the D,L-alteI'nating stereo-co-oligopeptide HCO-L-Phe-(DPhe-L-Phe),-OMe (I) forms three major species, two of which are dimeric and one tetrameric. One of the two dimeric species gives a specific set of 'H-nmr signals at 25°C; the other, together with the tetrameric species, gives another set of resonance signals. In a carbon tetrachloride or cyclohexane solution at 25"C, I forms virtually only the tetrameric species. From the nmr data, it can be shown that the dimeric and tetrameric species, that are in rapid equilibrium with each other in chloroform solutions, are a right-handed t tP5 helical dimer and the head-to-head (formylends-to-formylends) dimerization product of this dimer. It is suggested that the linear gramicidins may also form head-tohead dimers of parallel P helices, as observed for the model oligopeptide I.

📜 SIMILAR VOLUMES

Theoretical conformational analysis of t
Theoretical conformational analysis of the Gramicidin a transmembrane channel. I. Helix sense and energetics of head-to-head dimerization
✍ C. M. Venkatachalam; D. W. Urry 📂 Article 📅 1983 🏛 John Wiley and Sons 🌐 English ⚖ 728 KB

## Abstract Conformational energy calculations are presented for the head‐to‐head dimerized β helices for Gramicidin A transmembrane channel structures. The calculations take into account both left‐ and right‐handed β helices, and various side‐chain conformations. The energetics of the dimerization

A model of the temperature rise in the h
A model of the temperature rise in the head due to magnetic resonance imaging procedures
✍ T. Whit Athey 📂 Article 📅 1989 🏛 John Wiley and Sons 🌐 English ⚖ 417 KB

A simple model of power deposition in the head is presented in which the temperature increase in the head in general and, in particular, in a small spherical region of unperfused tissue contained within the head is calculated. The result of the calculation provides a limit on the SAR needed to ensur

Safety of, and biological and functional
Safety of, and biological and functional response to, a novel metallic implant for the management of focal full-thickness cartilage defects: Preliminary assessment in an animal model out to 1 year
✍ Carl A. Kirker-Head; David C. Van Sickle; Steve W. Ek; John C. McCool 📂 Article 📅 2006 🏛 Elsevier Science 🌐 English ⚖ 600 KB

## Abstract Focal full‐thickness cartilage lesions of the human medial femoral condyle (MFC) can cause pain and functional impairment. Affected middle‐aged patients respond unpredictably to existing treatments and knee arthroplasty may be required, prompting risk of revision. This study assesses th