* Brent crude sinks over $2.50 a barrel on groundbreaking Iran deal
* Agreement seen positive for risk appetite, global growth
* Yen skids to fresh lows, Nikkei and euro both benefit
SYDNEY, Nov 25 (Reuters) - Oil prices fell sharply on Monday after Iran and six world powers sealed a deal curbing its nuclear programme, a fillip for global economic growth that found expression in heartier share prices in Tokyo and Seoul.
The agreement gives Iran some relief from crippling sanctions and is considered a big step toward a more lasting treaty. While Iran will not be allowed to increase its oil sales for six months, any easing of Middle East tensions tends to lead to lower crude prices.
Brent crude oil shed $2.59 to $108.46 a barrel, its biggest daily drop in a month. U.S. oil lost 90 cents to $93.94 a barrel.
"Prices are reacting to the historic deal because it takes some of the risk premium out," said Ben le Brun, a market analyst at OptionsXpress in Sydney.
"But this news is hot off the press, and so there is some knee-jerk reaction. Oil may not fall much from here and we may see some paring back of losses."
Attention in Asia was again on Japanese markets as a sliding yen promises to boost exports and profits. The Nikkei sped ahead by 1.1 percent, having gained almost 11 percent in little more than two weeks.
On Wall Street, the Dow ended Friday with gains of 0.3 percent, while the S&P 500 added 0.5 percent for its first ever close above 1,800. Early Monday, S&P 500 futures had added another 0.4 percent.
But with money flooding into developed world assets, emerging markets are getting cold shouldered. It was notable that MSCI's broadest index of Asia-Pacific shares outside Japan failed to make any headway at all last week, even as Wall Street made new peaks.
Early Monday, the index was up 0.4 percent, as Seoul shares led the way with an increase of 1 percent.
In currency markets, the yen remained under pressure as investors use it for carry trades -- borrowing the currency at super-low rates to invest in higher-yielding assets elsewhere.
The dollar was up at 101.40 yen and threatening the July top of 101.53. Dealers said most of the action was in the euro against the yen, which has had a barnstorming run to reach four-year highs above 137 yen.
Euro-yen bulls now have their eyes set on a series of peaks from 2009 ranging from 137.43 all the way to 139.18, the top for that year. A break of the latter would take the euro to territory not visited since October 2008 and would be considered very bullish from a technical view.
Oddly, the gains have come even as the European Central Bank sounds ever more dovish on policy.
Over the weekend ECB Executive Board members Benoit Coeure and Joerg Asmussen both said the central bank was ready to take further action if necessary and instruments at its disposal included negative deposit rates.
Earlier on Monday, Coeure said slowing price growth, or disinflation, in Europe is likely to continue for now, but will not progress to deflation because the economy is recovering and inflation expectations remain anchored around 2 percent.
The single currency has been particularly strong against the Australian dollar, which was undone by threats of intervention from the Reserve Bank of Australia.
The euro leaped almost four full cents last week as the Australian currency crumpled to a three-month trough.
Traders said the commodity currency could continue to struggle particularly if tensions between China and Japan grew.
China at the weekend suddenly imposed new rules on airspace over islands at the heart of a territorial dispute with Tokyo, prompting Japan and ally the United States to warn of an escalation into the "unexpected".
There is no major economic data due in Asia on Monday, while most of the U.S. economic releases will be front-loaded this week ahead of the Thanksgiving holiday on Thursday.
The U.S. diary includes figures on housing starts and prices, consumer confidence, durable goods orders and manufacturing in the Chicago area.