Directed Evolution Via Phage Display

thescientist |  Caltech’s Frances Arnold, who advanced a technique called directed evolution to shape the function of enzymes, has received the Nobel Prize in Chemistry today (October 3). She shares the honor with George Smith, now emeritus professor of the University of Missouri, and Gregory Winter, emeritus group leader at the Medical Research Council Laboratory of Molecular Biology (LMB) in Cambridge, UK. Smith and Winter are both recognized for their work on a lab technique known as phage display in the directed evolution of new proteins—in particular, for the production of antibody therapeutics.

“I’d like to congratulate this year’s laureates for their tremendous breakthrough work in using chemistry to speed nature's own processes,” Peter Dourhout, president of the American Chemical Society, says in a statement. “The breakthroughs from these researchers enable that to occur thousands of times faster than nature to improve medicines, fuels and other products. This is truly directed evolution using chemistry.”

First reported by Smith in 1985, phage display involves the introduction of foreign DNA coding for a protein, such as an antibody, into a bacteriophage—a virus that infects bacteria. That protein is then displayed on the surface of the phage. Researchers can use these protein-displaying phages to screen for interactions with other proteins, DNA sequences, and small molecules. 

Speaking to the Associated Press this morning, Smith emphasized the role of others’ work in his achievement. “Very few research breakthroughs are novel,” he says. “Virtually all of them build on what went before. . . . That was certainly the case with my work.”

Winter, who cofounded the biotech company Cambridge Antibody Technology in 1989, developed the technique for the purpose of finding novel therapeutics. In 1993, his research group used phage display to successfully isolate fragments of human antibodies that could bind specific antigens. The genes for these fragments could be expressed in bacteria, the team reported, and could offer a “promising alternative” to mouse-based methods for the “production of antibodies against cell surface molecules.”

In 2002, adalimumab (Humira), a therapeutic produced by this approach, was approved by European and US regulators for the treatment of rheumatoid arthritis. Speaking in 2006, Winter called the approval “the sort of thing I’m most proud of.” The technique has since been used to isolate molecules against autoimmune diseases, multiple cancers, and bacteria such as Bacillus anthracis—the cause of anthrax.

RIP: The Late Great Otis Rush

Counterpunch |  Otis Rush was born in 1934 in Philadelphia, Mississippi, one of the most racially mixed towns in the Delta. In Rush’s youth the population of Philadelphia was almost equally divided between whites, blacks and Choctaw Indians. As a consequence, Philadelphia was also one of the most racist towns in Mississippi, a hotbed of Klan activity and, of course, site of the 1964 murders of civil rights workers Andrew Goodman, James Chaney and Michael Schwerner. In 1980, Reagan picked the Neshoba County Fair in Philadelphia as the locale  to give his first post-convention speech, an attack on the federal government that launched his own race-baiting “Southern Strategy.” J.L. Chestnut, one of two black people in the huge audience, recalled Ronald Reagan shouting  that “‘the South will rise again and this time remain master of everybody and everything within its dominion.’ The square came to life, the Klu (sic) Kluxers were shouting, jeering and in obvious ecstasy. God bless America.”

Like many black youths in the Delta, Otis sat near the radio every day at 12:15, tuning in to KFFA, broadcast out of Helena, Arkansas, for the King Biscuit Time show, hosted by Sonny Boy Williamson and Robert Lockwood, Jr. For half an hour Williamson and Lockwood played live in the studio, often featuring other rising stars of the blues, such as B.B. King, James Cotton and Pinetop Perkins (who was an original member of the studio band, called the King Biscuit Entertainers.) Otis decided he wanted to be a blues player. He began playing the blues harp at the age of six and later his father rigged him a makeshift one-string guitar out of a broom handle and baling wire.

Rush’s father was a sharecropper, toiling in the parched red clay soils of eastern Mississippi. But mechanization was slowly drawing this brutal way of life to a close. In 1948, Rush’s father moved the family (there were 8 Rush children) to Chicago. At the age of 14, Otis began working 12-hour days in the stockyards. At night he played the blues with two other young stockyard workers, Mike Netton, a drummer, and “Poor Bob” Woodfork, a guitar player recently migrated up from Arkansas. The band began to get some paying gigs in some of the new clubs springing up on Roosevelt Avenue.  One night when Rush was 18, Willie Dixon walked into the Alibi club on the West Side of town. Dixon, one of the true geniuses of American music, had just left Chess Records in a bitter dispute over royalties. The great bassist and arranger had taken a job with the new Cobra Records, a small Chicago label run by a TV repairman. Dixon was enthralled by Rush’s uniquely expressive, almost tortured guitar-style and signed him on the spot.

In the studio, Dixon, the real architect of the Chicago Blues sound, assembled a small talented R&B combo to back Rush, featuring Shakey Horton on harmonica, Harold Ashby on tenor, veteran drummer Odie Payne,  Little Brother Montgomery hammering the piano and Dixon himself on stand-up bass. The first song Rush recorded was Dixon’s “I Can’t Quit You, Baby.” Dixon said he wrote the song about an obsessive relationship Rush was having with a woman at the time. Dixon wanted to provoke an emotional response from the singer and he got one. “I Can’t Quit You, Baby” opens with a chilling falsetto scream, then Rush launches into a staccato guitar attack unlike anything heard before it. Led Zeppelin (and dozens of other bands) would cover Rush’s version of the song but never capture the excrutiating fervency of the original. The recording was released in the summer of 1956 as Cobra’s first single. The song hit number 6 on the Billboard R&B charts.

Over the next two years Rush and Dixon would release eight more records, each of them dazzlingly original. The sound was aggressive and confident, like the hard-charging jump blues “Violent Love,” where Rush’s slashing guitar chords seem to be engaged in a romantic combat with the horns. Rush’s own composition, “Checking on My Baby,” is an eerie, minor key blues that sweats sexual paranoia. This is not the blues of despondency and despair, but of defiance and, at times, rage. It’s music with an edge, sharpened by the metallic sounds of urban streets, of steel mills, jail cells and rail yards.