SEATTLE  The Seattle Post-Intelligencer will produce its last printed edition on Tuesday and become an Internet-only news source, the Hearst Corporation said on Monday, making it by far the largest American newspaper to take that leap.

But The P-I, as it is called, will resemble a local Huffington Post more than a traditional newspaper, with a news staff of about 20 people rather than the 165 it had, and a site with mostly commentary, advice and links to other news sites, along with some original reporting.

Other newspapers have closed and many more are threatened. But the transition to an all-digital product for The P-I will be especially closely watched in an industry that is fast losing revenue and is casting around for a new economic model.

For one thing, the closing may end up putting greater pressure on the surviving and financially struggling Seattle Times, because of the end of a joint operating agreement between the two papers. It may even bring closer the day when Seattle has no local paper at all.