April 25, 2007

MRC / Rib-X collaboration aims to fight drug resistance

Rib-X Pharmaceuticals, Inc. and the Laboratory of Molecular Biology of the Medical Research Council (MRC) have entered into a research collaboration in the area of ribosome and antibiotic interaction.

Under the terms of the collaboration, Rib-X and the MRC will jointly explore the high resolution crystal structure of the full 70S ribosome recently determined at the MRC Laboratory by a group led by world-renowned ribosome scientist, Dr Venki Ramakrishnan.

Dr Ramakrishnan received this year’s Louis-Jeantet Prize for Medicine for his work to identify the atomic structure of the ribosome, a small particle that uses the information encoded in genes to make proteins, which carry out a wide variety of functions in the cell. The ribosome is found in all living cells, including those of bacteria. Human and bacterial ribosomes are slightly different, making the ribosome a good target for antibiotic therapy that works by blocking the bacterium’s ability to make the proteins it needs to function.

Rib-X’s expert knowledge of the 50S structure has provided its scientists a novel and unique understanding of how antibiotics bind to the ribosome to block its function.

Rib-X is using these insights to build a clinical pipeline of differentiated compounds. The aim is to overcome antibiotics resistance which poses a serious threat to public health.

"It is a pleasure to be able to work with people who have such a high level of commitment to the utilization of the ribosome as a drug discovery target," said Dr. Ramakrishnan. "Rib-X has made remarkable strides in the relatively short life of the company and I am confident their extraordinary technology will serve an instrumental role in our collective quest for a new class of antibiotics."

“Rib-X is pleased to be able to collaborate with Dr. Ramakrishnan and the MRC in this important research area,” says Dr. Susan Froshauer, President and Chief Executive Officer of Rib-X. “We are excited about the possibility of providing new insights into how antibiotics interact at the atomic level with disease producing bacteria.”

Notes to editors:

About Dr. Ramakrishnan
Dr. Ramakrishnan is joint head of the Structural Studies Division at the Medical Research Council’s Laboratory of Molecular Biology in Cambridge. His research on the ribosome, which could help fight antibiotic resistant bacteria, has won the 2007 Louis-Jeantet Prize for Medicine. His achievements in determining the atomic structure of the 30S ribosomal subunit and its complexes with several antibiotics in 2000, and the entire ribosome in 2006 have won him international recognition.
Dr. Ramakrishnan earned his Bachelor of Science degree in physics from Baroda University in India and his Ph.D. in Physics from Ohio University. He pursued further post-graduate studies at The University of California, San Diego and moved to Cambridge in 1999 after a long career in the U.S. Dr. Ramakrishnan is a Fellow of the Royal Society and a Member of the U.S. National Academy of Sciences. He is a member of the Rib-X scientific advisory board.

About Rib-X Pharmaceuticals, Inc.
Rib-X Pharmaceuticals is a product-driven small molecule drug discovery and development company focused on the structure-based design of new classes of antibiotics. The company's underlying drug discovery engine capitalizes on its proprietary high-resolution crystal structure of the 50S subunit of the ribosome, which performs an essential role in the fundamental process of protein synthesis. Many known, commercially valuable antibiotics bind to the 50S, including those used to treat both community-acquired and hospital-acquired pathogens. The company's integrated research strategy, which combines state of the art, proprietary computational analysis, x-ray crystallography, medicinal chemistry, microbiology and biochemistry, allows it to rapidly synthesize new agents designed to avoid typical antibiotic resistance mechanisms. Rib-X's iterative intelligent engine has yielded several distinctive new antibiotic classes. The Company currently has two programs in Phase I, the Rχ-01 program as an oral/IV agent to treat serious hospital Gram-positive infections and the Rχ-03 program a next generation fluoroquinolone, active against methicillin-resistant Staphylococcus aureus.

For more information on the ribosome and the Rib-X mission, please visit the Company website at
www.rib-x.com.

About the Medical Research Council
The Medical Research Council is dedicated to improving human health through excellent science. It invests on behalf of the UK taxpayer. Its work ranges from molecular level science to public health research, carried out in universities, hospitals and a network of its own units and institutes. The MRC liaises with the Health Departments, the National Health Service and industry to take account of the public’s needs. The results have led to some of the most significant discoveries in medical science and benefited the health and wealth of millions of people in the UK and around the world. www.mrc.ac.uk.