Centrica, the energy company which owns British Gas, is hoping to become the leading business-to-business (B2B) gas supplier in the Eastern US through the purchase of a unit of Hess Corporation.Centrica's North American subsidiary Direct Energy Business is to buy the New Jersey-based Energy Marketing business of Hess for $731m (£478m) in cash plus net working capital (estimated at around $300m).The firm said that the acquisition will further integrate its existing energy supply activities along the gas value chain, linking gas supply from producers through secured transport and storage to the gas and power customer base.The Hess unit generated over $6.0bn of revenues in 2012."This transaction will transform our B2B operations in North America, giving us leading positions in business gas and power supply and creating a unique dual fuel business in the US," said Centrica's Chief Executive Sam Laidlaw."It marks a significant step towards delivering on our strategy - substantially increasing the scale of our North American downstream business and integrating along the gas value chain - with the aim of doubling the profitability of our North American downstream business over the next three-five years," he said.Centrica's share price was trading 1.61% higher at 383.9p in mid-morning trade on Tuesday.BC