Biomaterial Database

Optimization of the in vitro packaging efficiency of bacteriophage T7 DNA: effects of neutral polymers. 1989

M Son, and S J Hayes, and P Serwer

Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284-7760.

The in vitro DNA packaging of several DNA bacteriophages is stimulated by the presence of neutral polymers. To optimize bacteriophage T7 DNA packaging and to understand the basis for optimization, the efficiency of T7 DNA packaging has been determined at completion, as a function of the type, molecular mass, and concentration of the polymer added. When the polymer used was polyethylene glycol (PEG) of 0.2, 0.6 or 12.6 kDa, the efficiency of DNA packaging reached maximum at an intermediate concentration of polymer. The osmotic pressure (Pos) at maximum efficiency was either in, or close to, the range of colloid Pos measured for the intact host cell. The optimum Pos increased as the size of the polymer used decreased. PEG-100 (of 0.1 kDa) did not stimulate in vitro T7 DNA packaging. Dextran of 10 kDa also stimulated packaging and produced maximum efficiency at a physiological Pos. The degree of stimulation increases as DNA packaging extract concentration decreases; stimulation by as much as two to three orders of magnitude is observed. The presence of added polymer reduces fluctuations in DNA packaging efficiency caused by variability in the concentration of DNA packaging extracts. For reproducible and high efficiency packaging, the dextran was more reliable than the PEGs, possibly because the Pos of the dextran solutions is less sensitive to polymer concentration than is the Pos of PEG solutions. The optimum concentration of dextran at completion was also the optimum at all times before completion.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D011092	Polyethylene Glycols	Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.	Macrogols,Polyoxyethylenes,Carbowax,Macrogol,Polyethylene Glycol,Polyethylene Oxide,Polyethyleneoxide,Polyglycol,Glycol, Polyethylene,Glycols, Polyethylene,Oxide, Polyethylene,Oxides, Polyethylene,Polyethylene Oxides,Polyethyleneoxides,Polyglycols,Polyoxyethylene
D002213	Capsid	The outer protein protective shell of a virus, which protects the viral nucleic acid. Capsids are composed of repeating units (capsomers or capsomeres) of CAPSID PROTEINS which when assembled together form either an icosahedral or helical shape.	Procapsid,Prohead,Capsids,Procapsids,Proheads
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D003911	Dextrans	A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.	Dextran,Dextran 40,Dextran 40000,Dextran 70,Dextran 75,Dextran 80,Dextran B-1355,Dextran B-1355-S,Dextran B1355,Dextran B512,Dextran Derivatives,Dextran M 70,Dextran T 70,Dextran T-40,Dextran T-500,Hemodex,Hyskon,Infukoll,Macrodex,Polyglucin,Promit,Rheodextran,Rheoisodex,Rheomacrodex,Rheopolyglucin,Rondex,Saviosol,Dextran B 1355,Dextran B 1355 S,Dextran T 40,Dextran T 500
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D013268	Stimulation, Chemical	The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.	Chemical Stimulation,Chemical Stimulations,Stimulations, Chemical
D013604	T-Phages	A series of 7 virulent phages which infect E. coli. The T-even phages T2, T4; (BACTERIOPHAGE T4), and T6, and the phage T5 are called "autonomously virulent" because they cause cessation of all bacterial metabolism on infection. Phages T1, T3; (BACTERIOPHAGE T3), and T7; (BACTERIOPHAGE T7) are called "dependent virulent" because they depend on continued bacterial metabolism during the lytic cycle. The T-even phages contain 5-hydroxymethylcytosine in place of ordinary cytosine in their DNA.	Bacteriophages T,Coliphages T,Phages T,T Phages,T-Phage